Part I. Synthesis and Molecular Assemblies of d10 Metal

Complexes Bearing 9, 10-Disubstituted

Anthracene Ligand

Part II. Synthesis and Spectroscopic Studies of

Heterobimetallic Platinum(II)-acetylide and

Platinum(0)-acetylene Complexes

ZHANG KE (B.Sci., Beijing University)

A THESIS SUBMITTED

FOR THE DEGREE OF PHD OF SCIENCE

DEPARTMENT OF CHEMISTRY

NATIONAL UNIVERSITY OF SINGAPORE

2006

i

Acknowledgement

This thesis is a result of four years work whereby I have been accompanied and

supported by many people. It is a pleasant aspect that I have now the opportunity to

express my gratitude for all of them.

The first person I would like to thank is my supervisor Dr. Yip, Hon Kay John, who has

provided me continuous care and guidance on my research work. His overly enthusiasm

on research has made a deep impression on me. Not only the knowledge but also the

scientific attitude, which I learned from him, will be great fortune to me in my future

career and life.

I would like to thank the colleagues in our research group: Mr. Lin Ronger, Dr. Wu

Jianguo, Mr. Hu Jian, Dr. Xu Huan and Miss. Wang Yuanyuan. From all of them, I have

received great help on my experiments and valuable discussion. My special thanks are

given to Miss. Tan Geok Kheng and Prof. Koh Lip Lin for their assistance on crystal

structure analysis. I appreciate Dr. Wang Kwok-Yin for his assistance on electrochemical

measurements of a series of my complexes. I also thank Dr. Leong Weng Kee for his

providing me some of the starting materials. It is my pleasure to give my thanks to all the

staffs in the Chemical, Molecular and Materials Analysis Centre (CMMAC) at the

Department of Chemistry in National University of Singapore for their assistance on

characterization of my compounds.

I want to show my acknowledgement to the National University of Singapore for the

scholarship to pursue my Ph. D. degree.

Finally, I am indebted to my beloved parents and wife. Their infinite encouragement

endowed me with confidence to complete this thesis.

ii

Table of Contents

Acknowledgements……………………………………………………………………… i

Table of Contents…………………………………………………………………...........ii

List of Abbreviations…………………………………………………………………….v

Summary…………………………………………………………………………………vi

Part I. Synthesis and Molecular Assemblies of d10 Metal Complexes

Bearing 9, 10-Disubstituted Anthracene Ligand

Chapter 1. Roles of Anthracene Unit in Inorganic Chemistry

1.1 A luminophore for chemosensors……………………………………………………..3

1.2 �-coordinating to metal cations………………………………………………………..3

1.3 A bridging unit in crystal engineering………………………………………………...4

1.4 Phosphorus-substituted anthracenes…………………………………………………..5

1.5 Use of the anthracene unit in our group……………………………………………….6

1.6 Objectives……………………………………………………………………………..9

Chapter 2. Molecular Assemblies of AuI Complexes with 9, 10-

Bis(diphenylphosphino)anthracene Ligand

2.1 Introduction…………………………………………………………………………..11

2.1.1 Au-Au interaction……………………………………………………………...11

2.1.2 �-� interaction………………………………………………………………….13

2.1.3 Objectives……………………………………………………………………...15

2.2 Results and discussion……………………………………………………………….16

2.2.1 Synthesis and characterization…………………………………………………16

2.2.2 Crystal structures………………………………………………………………18

2.2.3 Electronic absorption and emission spectroscopy……………………………..34

2.3 Conclusions…………………………………………………………………………..41

2.4 Experimental section…………………………………………………………………42

Chapter 3. First Examples of AuI-X-AgI Halonium Cations

iii

3.1 Introduction…………………………………………………………………………. 45

3.2 Objectives……………………………………………………………………………46

3.3 Results and discussion……………………………………………………………….47

3.4 Conclusions…………………………………………………………………………..51

3.5 Experimental section…………………………………………………………………52

Chapter 4. Systhesis, Structures and Electronic Spectroscopy of

d10 Metal Complexes with 9, 10-Anthracenedithiol Ligand

4.1 Introduction…………………………………………………………………………..55

4.2 Objectives……………………………………………………………………………56

4.3 Results and discussion……………………………………………………………….57

4.3.1 Synthesis and crystal structures………………………………………………..57

4.3.2 Electronic absorption and emission spectroscopy……………………………..65

4.4 Conclusions…………………………………………………………………………..68

4.5 Experimetal section…………………………………………………………………..69

Part II. Synthesis and Spectroscopic Studies of Heterobimetallic Platinum(II)-

acetylide and Platinum(0)-acetylene Complexes

Chapter 5. Introduction on Metal Acetylide/Acetylene Complexes of

Electrochemical and Photophysical Properties

5.1 Mixed-valence complexes…………………………………………………………...75

5.2 C�C based bridges in mediating electronic communication………………………...79

5.3 Photophysical properties……………………………………………………………..82

5.4 Objectives……………………………………………………………………………84

Chapter 6. Synthesis and Electrochemical Studies of Heterobimetallic

Platinum(II) Ferrocenylacetylide Complexes

6.1 Introduction…………………………………………………………………………..89

6.2 Results and discussion……………………………………………………………….89

iv

6.2.1 Synthesis and characterization…………………………………………………90

6.2.2 Crystal structures………………………………………………………………95

6.2.3 Electronic absorption spectroscopy…………………………………………..106

6.2.4 Electrochemistry……………………………………………………………...109

6.3 Conclusions…………………………………………………………………………117

6.4 Experimental section………………………………………………………………..118

Chapter 7. Synthesis and Photophysical Studies of a Series of

Platinum(0)-acetylene Complexes

7.1 Introduction…………………………………………………………………………126

7.2 Results and discussion……………………………………………………………...128

7.2.1 Synthesis and characterization………………………………………………..128

7.2.2 Crystal structures……………………………………………………………..130

7.2.3 Electronic spectroscopy………………………………………………………134

7.3 Conclusions…………………………………………………………………………144

7.4 Experimental section………………………………………………………………..145

Physical Measurements...……………………………………………………………..149

References……………………………………………………………………………...153

Publications……………………………………………………………………………175

Appendices…………………………………………………………………………….176

v

List of Abbreviations

AnSSAn di-9-anthryl disulfide

bipy 4, 4’-bipyridine

tBu2bpy 4, 4�-di-tert-butyl-2, 2�-bipyridine

COD 1, 5-cyclooctadiene

dcypm bis(dicyclohexylphosphino)methane

dmpm 1, 2-bis(dimethylphosphino)methane

dppf 1, 1�-bis(diphenylphosphino)ferrocene

dppm bis(diphenylphosphino)methane

dppp 1, 3-bis(diphenylphosphino)propane

Fc ferrocenyl

HOMO highest occupied molecular obital

H2SAnS 9, 10-anthracenedithiol

LMCT ligand-metal charge-transfer

LUMO lowest unoccupied molecular obital

MLCT metal-ligand charge-transfer

NS22- 1, 8-naphthalenedithiolate

NLO nonlinear optical

OTf- triflate anion

PAnP 9, 10-bis(diphenylphosphino)anthracene

SAnS2- 9, 10-anthracenedithiolate

S-tmhd thiolate of 5-mercapto-2,2,6,6-tetramethyl-4-hepten-3-one

TBAH tetrabutylammonium hexafluorophosphate

vi

Summary

Group 10/11 transition metal complexes are of considerable interest due to their

structural diversities and great potential for developing novel materials of molecular scale

in various fields such as optical, electronic and medical materials. This thesis consists of

two parts of work on the synthesis and characterization of metal complexes of these two

groups. The objective of the first part of work was to develop d10 complexes of

interesting structural properties by utilizing metal-metal and/or �-� interactions for

assembling molecules. In the second part, to search for novel molecules of electronic and

optical properties, spectroscopy of a series of heterobimetallic platinum(II)-acetylide and

platinum(0)-acetylene complexes were studied.

In the first part of work, AuI diphosphine complexes formulated as (�-PAnP)(AuX)2

(PAnP: 9, 10-bis-diphenylphosphinoanthracene; X: Cl(1), Br(2), I(3), NO3(4), -C�CPh(5),

-C�CC14H9(6)) were prepared and structurally characterized by X-ray diffraction analysis.

Molecules in crystals of 1·CH2Cl2, 3·CH2Cl2, 4·0.5Et2O and 5·THF form dimers via both

Au-Au and �-� interactions (between anthracene units), whereas those in 1·0.5Et2O,

2·Et2O and 2·2CH2Cl2 dimerize only through the latter. Intermolecular edge-to-face �-�

interactions were observed in 6·0.75CH2Cl2 to dominate over Au-Au interactions, face-

to-face and off-set �-� interactions. All these complexes show strong ligand-centered

fluorescence. Slow diffusion of THF solution of AgSbF6 into CH2Cl2 solution of

complexes 1 or 2 gives rise to the formation of novel AuI-X-AgI halonium complexes

({[(�-PAnP)(AuCl)2]2Ag}+SbF6- (7) or {[(�-PAnP)(AuBr)2]2Ag}+SbF6

- (8)), structures of

which are stabilized by the collective actions of Ag-X and Au-Ag and �-� interactions.

Reaction of 9, 10-anthracenedithiol H2SAnS with different starting materials ([Cu2(�-

vii

dppm)2(CH3CN)2](PF6)2, [Ag2(�-dppm)2](ClO4)2 and PPh3AuCl) (dppm: bis-

diphenylphosphinomethane) formed three different d10 metal thiolates: [(Cu2(�2-

dppm)2)2(�2-�2-SAnS)](PF6)2 (9), [(Ag2(�2-dppm)2)2(�2-�2-SAnS)](ClO4)2 (10) and

(Ph3PAu)2(�-SAnS-SAnS) (11). The anthracene unit plays a key role in stabilizing the

structures of these complexes by forming �-� interactions. The ligand H2SAnS and

complexes 9-11 all show intense ligand-centered emissions (��* and n�*) in degassed

solution.

In the second part of work, PtII-acetylide complexes formulated as trans-(Fc-C�C-

)2Pt(�-dppm)2M(L) (Fc: ferrocenyl; M(L): nothing(12), Au(ClO4)(13), Ag(NO3)(14),

Cu(PF6)(15), Hg(Cl2)(16), Rh(CO)(PF6)(17), W(CO)3(18), Mo(CO)3(19)) were

synthesized. Crystal structure results show the presence of intramolecular Pt���M

interaction in 13-19. The heterogeneous metal atom M also coordinates to one or both

carbon atoms of one of the C�C bonds attached on Pt in 15, 17, 18 and 19. UV-visible

spectroscopic studies show that metal-metal interactions exist in solution for 13-17. The

voltammetric data show that while the electronic communications in 13 and 14 are as

poor as that in mononuclear complex trans-Pt(C�CFc)2(PPh2Me)2 (20), Pt���Hg

interaction in 16 can enhance electronic communication along the C�C-Pt-C�C bridge.

In addition, electronic spectroscopic properties of a series of platinum(0)-acetylene �

complexes (Pt(PPh3)2(PhC2Ph) (21), Pt(dppp)(PhC2Ph) (22), Pt(PPh3)2(PhC4Ph) (23),

Pt(dppp)(PhC4Ph) (24), (Pt(dppp))2(PhC4Ph) (25), Pt(dppp)(CH3C4CH3) (26) and

(Pt(dppp))2(CH3C4CH3) (27)) (dppp: 1, 3-bis(diphenylphino)propane) were investigated

in the second part of work. All these complexes show interesting MLCT

phosphorescence in both solid state and frozen solution.

1

Part I.

Synthesis and Molecular Assemblies of d10 Metal Complexes

Bearing 9, 10-Disubstituted Anthracene Ligand

2

Chapter 1

Roles of Anthracene Unit in Inorganic Chemistry

3

For many years the anthracene unit has attracted great attention from both organic and

inorganic chemists, as anthracene derivatives play an important role in designing of

luminescent materials1 both in solutions and in the solid state, for example, for phosphors

and lasers.2 The large delocalization of � electrons in the aromatic plane endows these

compounds with rich photophysics and photochemistry.

1.1 A luminophore for chemosensors

As a luminophore, an anthracene unit has been introduced into chemosensors designed

either to detect alkali, alkaline-earth,3 transition metal cations4 or, more recently, even

anions5 like halides, acetate and dihydrogenphosphate.6 The basic strategy in the

construction of these sensor molecules is to substitute the anthracene moiety in the 9-

position or 9- and 10- positions with remote chelating groups (e. g. a crown ether group)

that are capable of trapping ions by means of hydrogen bonds or electrostatic

interactions with neutral or positively charged sensor molecules.7 Some transition metal

complexes synthesized by this method have been found to behave like logic gates by

switching the fluorescence of anthracene moiety on/off upon changing the oxidation

state of the metal center, as the oxidation state of the metal determines whether there is an

energy/electron transfer from the photoexcited state of the luminophore to the metal to

quench the emission (an example system is illustrated in Scheme 1.1).8

1.2 �-coordinating to metal cations

Besides serving as a luminophore, the anthracene unit itself can also coordinate to metal

cations through an �6 �-coordination mode. Novel phosphine molecule sensors have been

synthesized in this strategy recently.9 As illustrated in Scheme 1.2, an emissive

4

CH2 N

S

S

SCuI

no energy transfer

h� h�'

emissive

CH2 N

S

S

SCuII

energy transfer

h�

nonemissive

oxidizing

reducing

anthraceno-diphosphine ligand L reacted with a d10 metal cation M+ to give the

nonemissive �6 complex LM+, which could further react with a tertiary phosphine

forming complex LMP+ to switch on the fluorescence by breaking the �-coordination

between the anthracene unit and the metal.

N

N

PPh2

Ph2P

N

N

PPh2

PPh2

M

N

N

PPh2

PPh2

M

N

N

PPh2

PPh2

M PR3

M+PR3

L LM+ (nonemissive) intermediate LMP+ (emissive)

+ + +

M = Cu, Ag or Au; PR3 = P(n-Bu)3, HPPh2 or PPh3

1.3 A bridging unit in crystal engineering

Scheme 1.1. An example system mimicing a logic gate using the anthracene unit as a luminophore

Scheme 1.2. A series of �-coordination complexes of an anthracene-containing ligand

5

9, 10-Disubstitued anthracene derivatives are important building blocks in crystal

engineering.10 For instance, recently Mirkin and co-workers have used a designed

anthracene-containing bidentate ligand to synthesize a metallocyclophane which could

trap an aromatic molecule to form a triple-layered complex with novel photophysical

properties.10d The synthetic strategy of this system is shown in Scheme 1.3.

OO PPh2Ph2P

OO PPh2Ph2P

RhRh

OO

OO

Ph2PPPh2

PPh2 Ph2PRhRh

NCCH3

NCCH3

H3CCN

H3CCNCH3CN

2+2BF4- 2+2BF4

-

OO

OO

PPh2

PPh2 PPh2

PPh2

Rh Rh NCCH3H3CCN R

2+2BF4-

R1 eq.

R =

NCCN

NCCN

or

1.4 Phosphorus-substituted anthracenes

While there are many reports describing oxygen-,10a, c, d, 11 nitrogen-12 and silicon-

substituted13 anthracene derivatives, relatively few studies have been reported on the

phosphorus-substituted anthracenes. Schmutzler and co-workers synthesized the first

Scheme 1.3. Construction of a triple-layered metallocyclophane system using anthracene moieties as key bridging units

6

monophosphorus derivative substituted in the 9-position,14 and subsequently its

properties as a ligand for d-block metals were investigated.15 1, 8-

Bis(diphenylphosphino)anthracene serves as a neutral chelating donor ligand in transition

metal chemistry.16 More recently, Kubiak and co-workers has synthesized the ligand {1-

(9-anthracene)phosphirane}, and investigated the structural properties of its platinum(II)

complexes (Figure 1.1).17 While the molecular structure of complexes A and B are

dominated by intramolecular �-stacking between the anthracene rings, that of complex C

shows significant intermolecular �-stacking between anthracene rings of two adjacent

molecules.

P

P

PtCl

Cl

P

P

Pt

S

S

CN

CN

P

P

PtS

S

CO2Et

CO2Et

P

P

Pt

S

S

NC

NC

A B

C

1.5 Use of the anthracene unit in our group

Figure 1.1. Structures of three platinum(II) complexes of the ligand {1-(9-anthracene)phosphirane}

7

However, to our knowledge, the coordination chemistry of diphosphorus-substituted

anthracenes at 9- and 10-positions has not been studied yet. Therefore, the ligand 9, 10-

bis(diphenylphosphino)anthracene (PAnP) has been synthesized in our group and utilized

as a building block in crystal engineering of d10 metal complexes. The preparation of the

ligand is shown in Scheme 1.4. Treatment of PAnP with one equivalent of AuI ions

Br

Br

Li

Li

PPh2

PPh2

2 eq. n-BuLi, ether

ice bath

2 eq. Ph2PCl

r.t.

PAnP

produced a fluorescent trinuclear gold ring [Au3(�-PAnP)3�(ClO4)](ClO4)2 (Figure

1.2) that has structure and fluxionality reminiscent of cyclohexane, while the reaction

Scheme 1.4. Synthesis of the ligand PAnP

Ph2P PPh2

Ph2P

Ph2PPPh2

PPh2

Au Au

Au

= perchloride anion

Figure 1.2. Structure of a trinuclear gold ring [Au3(�-PAnP)3�(ClO4)](ClO4)2 (one anion is inside the ring, while the other two are outside.)

8

between one equivalent of the ligand and two equivalents of (Me2S)AuX (X = Cl or Br)

gave the dinuclear gold complexes (�-PAnP)(AuX)2 ( X = Cl, (1); Br, (2)) (Figure

1.3).18 In addition, with the help of another bridging ligand 4, 4’-bipyridine (bipy), a

tetranuclear gold rectangle [Au4(�-PAnP)2(�-bipy)2](OTf)4 (OTf-: triflate anion) was

obtained (Figure 1.4).19 It shows a large rectangular cavity of 7.921(3) × 16.76(3) Å,

which makes it capable of hosting aromatic molecules via �-� interaction with the bipy

rings.

Figure 1.3. Structures of the dinuclear complexes (�-PAnP)(AuX)2 ( X = Cl, (1); Br, (2))

Ph2P

Ph2P

Au

Au

Ph2P

Ph2P

Au

Au

Cl

Cl

Br

Br

1 2

Ph2P

Ph2P

Au

Au N

N

PPh2

PPh2

Au

AuN

N

4+

4OTf-

OTf- = triflate anion

Figure 1.4. Structure of the tetranuclear gold rectangle [Au4(�-PAnP)2(�-bipy)2](OTf)4

9

1.6 Objectives

As an extended study of the coordination chemistry of PAnP, a portion of present work

was to investigate the ancillary ligand effect on the crystal engineering of the dinuclear

gold complex (�-PAnP)(AuX)2 by using different ancillary ligand X ( X = halide, nitrate

or acetylide). The molecular structures of (�-PAnP)(AuCl)2 (1) and (�-PAnP)(AuBr)2 (2)

show no Au-Au interaction.18b However, the packing of these molecules are not discussed

in our previous study. In fact, these molecules are packed in dimers via �-� interaction

between neighboring anthracene rings. As the intermolecular Au-Au seperation of

phosphinegold(I) complexes depends on the nature of the ancillary ligand,20 changing the

ancillary ligand of (�-PAnP)(AuX)2 may help us understand how Au-Au and �-�

interactions cooperate or compete with each other in crystal engineering. The results

(including a more detailed structural study of complexes 1 and 2) are given in the next

chapter. In addition, treatment of complexes 1 and 2 with AgSbF6 led to an

unprecedented discovery of the existence of AuI-X-AgI haloniums, which is discussed in

Chapter 3. Being intrigued by the novel results obtained from the ligand PAnP, we were

wondering if displacement of phosphorus with other coordinating element such as sulfur

would lead to another interesting ligand. Therefore, another objective of the present work

was to synthesize a designed ligand 9, 10-anthracenedithiol (H2SAnS, Figure 1.5) and

investigate its coordination chemistry with d10 metals. Results of this portion of work are

given in Chapter 4.

SH

SH

Figure 1.5. Structure of 9, 10-anthracenedithiol (H2SAnS)

10

Chapter 2

Molecular Assemblies of AuI Complexes with 9, 10-Bis(diphenylphosphino)anthracene Ligand

11

2.1 Introduction

Gold(I) phosphine complexes have received great attention for many years.21-23 Because

of the soft acid nature of gold(I), P-donor ligands as soft bases have a strong affinity for

gold(I) centers. Though a three-24 or four-coordinate24a, 25 gold(I) center has been

observed in many phosphine complexes, two-coordinate with a linear geometry is the

most common coordination mode for gold(I) atoms. Extensive studies of gold(I)

phosphine complexes have been initiated on various aspects such as crystal

engineering,24-28 photophysics29 and biomedical activities.30 Many interesting structural

or photophysical properties of these complexes are related to the presence of Au-Au

interaction.

2.1.1 Au-Au interaction

Schmidbaur firstly coined the term “aurophilic attraction” to exclusively refer to the Au-

Au interaction in gold complexes.31 It is now recognized and accepted that small (not

stereochemically inhibited) mononuclear complexes undergo intermolecular aggregation

via short sub-van der Waals gold-gold contacts of ca. 3.05 Å associated with a bond

energy of the order of 5-10 kcal/mol.32 A database study of Au-Au interactions by

Desiraju33 revealed that such contacts were usually within a range of 2.5 to 4 Å (Figure

2.1).

2.5-4 Å

Figure 2.1. Au-Au interaction

X Au Y

X'Au

Y'

12

A number of detailed computational studies have been done on Au-Au interaction based

on different models and approaches. Eisenstein and Schweizer studied R3PAu···AuPR3

interactions in such molecules containing main group atoms by Extented Hückel

calculations.34 Pyykkö’s group have investigated the dependence of the Au-Au

interaction in perpendicular model systems of the type [(ClAuPH3)2] on the ab initio

method, basis set and different pseudopotentials used, and on relativity.35 More recently,

fifteen molecules containing the AuI species were calculated by ab initio HF and MP2

methods and by five different density functional approaches to investigate the aurophilic

bonding mechanism by Schwarz and co-workers.36

Extensive experimental investigations have been reported on the consequence of Au-

Au interaction on the supramolecular chemistry of gold compounds. X-ray diffraction

studies show that via Au-Au interaction gold complexes are often associated with dimers,

trimers, tetramers and chains. Some specific reported examples are illustrated in Figure

2.2, and this kind of non-covalent interaction has also been utilized to synthesize

Au

Me2PhP

Br

Au

PPhMe2

Br

Dimer: {(Me2PhP)AuBr}2 28c

Au

Me2PhP

Cl

Au

PPhMe2

Cl AuPPhMe2

Cl

Trimer: {(Me2PhP)AuCl}3 28c

Tetramer: {(t-BuN�C)Au(C�CSiMe3)}4 37

Au

C

SiMe3

N

t-Bu

AuC

Me3Si

Nt-Bu

Au

C

SiMe3

Nt-Bu

Au

C

SiMe3

N

t-Bu

Chain: {(Me3P)AuCl}n 26j

Au

Cl

Me3P

Au

Cl

Me3P

Au

Cl

Me3P

Au

Cl

Me3P

Au

Cl

Me3P

Au

Cl

Me3P

Figure 2.2. Examples of oligomers of gold complexes via Au-Au interaction

13

macrocyclic complexes. For example, Puddephatt and co-workers have reported the

synthesis and structures of large gold rings by bridging bidentate-phosphine gold

moieties ([Au(�-dcypm)Au]2+ or [Au(�-dppm)Au]2+, dcypm =

bis(dicyclohexylphosphino)methane, dppm = bis(diphenylphosphino)methane) with 4,4’-

phenyldiisocyanide27e or 4,4’-bipyridine (Figure 2.3).27j The strategy for assembling

such macrocycles is based on the orienting effects of weak Au-Au interaction in the

binuclear precursor molecules. This research group also discovered the first family of

organometallic catenanes which are formed by self-assembly from the components of

[{X(C6H4OCH2CCAu)2}n], an oligomeric digold(I) diacetylide, and Ph2P(CH2)nPPh2, a

diphosphine ligand.27h When the diphosphine ligand is 1, 3-

bis(diphenylphosphino)propane, the two rings of the catenane are observed to interact

with each other via Au-Au interactions (Figure 2.4).

2.1.2 �-� interaction

Besides metal-metal interactions, the interactions between ligands are another important

factor in crystal engineering of late transition metal complexes. One of the most common

P h 2 P

P h 2 P

A u

A u

N

N

N

N

A u

A u

P P h 2

P P h 2

C y 2 P

C y 2 P

A u

A u

C

C

N

N

N

N

C

C

A u

A u

P C y 2

P C y 2

4 +

4 +C

Me

Me

O

O

CH2

CH2

C

C

C

C

Au

Au

PPh2

PPh2

C

Me

Me

O

O

H2C

H2C

C

C

C

C

Au

Au

Ph2P

Ph2P

Figure 2.3. Examples of gold(I) macrocycles

Figure 2.4. An example of gold(I) catenane

14

types of ligand interactions is �-� interaction, which is often observed in compounds

bearing large aromatic groups.

�-� interaction, a term referring to a strong attractive interaction between �-systems, has

been known for over half a century. Sanders and co-workers have shown that the simple

picture of a �-system as a sandwich (Figure 2.5) of the positively charged �-framework

between two negatively charged �-electron clouds accounts well for the

observed interactions between �-systems.38 It is a �-� attraction rather than a �-�

electronic interaction which leads to favorable interactions. These electrostatic effects

determine the geometry of interaction, while van der Waals interactions (and solvophobic

effects) make the major contribution to the magnitude of the observed interaction. There

are three different typical geometries of this interaction (shown in Figure 2.6). The

separation of the two parallel packed aromatic planes is usually in a range of 3.3-3.8 Å39

for face-to-face and offset geometries, while for edge-to-face geometry the distance

between the centroids of the two arenes is usually in a range of 4.5-7 Å with a dihedral

angle of 30-90º between two aromatic planes.40 �-� interactions control such diverse

phenomena as the vertical base-base interactions which stabilize the double helical

structure of DNA,41 the interaction of drugs into DNA,42 the packing of aromatic

molecules in crystals,43 the tertiary structures of proteins,44 the conformational

+++

++

+

- - -

- --

�-electron clouds positively charged �-framework

Figure 2.5. The sandwich structure of a simple �-system

15

preferences and binding properties of polyaromatic macrocycles,45 and complexation in

many host-guest systems.46

2.1.3 Objectives

While both Au-Au and �-� interaction have been largely reported to be used as protocol

in crystal engineering, few examples are reported in the literature to describe the use of

the cooperation of such two kinds of interactions as a means of generating extended or

supramolecular structures. Eisenberg’s group reported two AuI pyrimidinethiolate

compounds including a dimer that possesses a solid state structure in which �-� stacking

clearly dominates over intermolecular Au-Au interaction.47 Onaka and coworkers have

reported structures of a tetramer of {(Ph3P)Au(SPh)}4 and a polymer of {(�-trans-

Ph2PCH=CHPPh2)[Au(SPh)]2}n, which are formed via intermolecular Au-Au interactions

and �-� interactions between the phenyl rings of the phosphine and/or the phenylthiolate

groups.48a, b This research group has also studied the substituent effects on Au-Au and �-�

interaction in crystals of a series of monodentate arylphosphine gold(I) complexes

formulated as R3PAuX (R = m-H3CC6H4, p-H3CC6H4, m-F3CC6H4 , p-F3CC6H4 or 3, 5-

(F3C)2C6H3; X = chloride, phenylthiolate or 4-pyridylthiolate) and concluded that most

face-to-face offset edge-to-face

Figure 2.6. Geometries of �-� interactions

16

dimers of these complexes constructed by Au-Au interaction appeared to be reinforced by

�-� interaction between the phenyl ring of phenylthiolate group or the pyridinyl ring of 4-

pyridinylthiolate group and one of the phenyl rings of the R3P ligand.48c More recently,

Tzeng and co-workers investigated the coordination chemistry of 2-mercapto-4-methyl-5-

thiazoleacetic acid with gold(I) revealing a tetranuclear [Au(SSCOOH)]4 complex

forming a one-dimensional channel structure via Au-Au and �-� interaction.49

Nevertheless, studies of the cooperation of �-� and Au-Au interactions in crystal

engineering of gold complexes remain quite limited. As both Au-Au and �-� interactions

have been largely reported to form various novel structures, the co-existence of these two

interactions in one structure is expected to lead to some interesting supramolecular

chemistry. Thus, this part of our work is to use Au-Au interaction in conjunction with �-�

interaction as a means of generating extended structures, based on the system of a series

of gold(I) complexes (�-PAnP)(AuX)2 (X = Cl, (1); Br, (2); I, (3); NO3-, (4); PhC�C-, (5);

AnC�C-, (6), An = 9-anthracenyl) as mentioned in the first chapter. The large �-

conjugation system of the anthracene ring was expected to form intermolecular �-�

interactions in the structures of these complexes. Different ancillary ligands X were

introduced to tune the electron density of the gold(I) centre which is a key factor in

controlling Au-Au separations.

2.2 Results and discussion

2.2.1 Synthesis and characterization

The synthesis routes for complexes 1 to 6 is shown in Scheme 2.1. Complexes 1 and 2

were prepared by ligand substitution of a strong donor PAnP for a weak donor Me2S,

which is commonly used for synthesis of phosphine gold(I) halides. Due to the fact that

17

1 equiv. of AuI3

MeOH

PAnP

2 equiv. of (Me2S)AuX

X= Cl, 1X= Br, 2

CH2Cl2

Ph2P

Ph2P

Au

Au

Ph2P

Ph2P

Au

Au

Ph

Ph

PPh2

PPh2

Ph2P

Ph2P

Au

Au

I

I

Ph2P

Ph2P

Au

Au

ONO2

ONO2

Ph2P

Ph2P

Au

Au

X

X

3

4

5

6

excess of AgNO3

CH2Cl2

X=Cl and KOH

MeOH

excess of phenylacetylene

SiMe3

excess of

and KOH

MeOH

Scheme 2.1. Synthesis of complexes 1-6

18

Me2SAuI is much more thermally unstable and light sensitive than its chloride and

bromide analogues, complex 3 was prepared by direct reduction of AuI3 by half mol

equivalent of PAnP and immediate coordination of another half to gold(I). Complex 4

was prepared from complex 1 by straightforward precipitation of chloride by AgNO3.

Complexes 5 and 6 were prepared by metathesis reaction (from chloride to acetylide) in

alcohol solvent. All the reactions gave moderate to good yields. All these complexes are

infinitely stable in solid state, while they decompose gradually to gold metal in solution

in the presence of light. The 31P{1H}-NMR spectra of complexes 1 to 6 all display only a

singlet, showing that two P atoms of PAnP are symmetric in solution. The chemical shifts

of the halides are in an increasing order of Cl-<Br-<I-, which follows the periodic trend

that is seen for other phosphine gold(I) halides.28c, 50 The IR spectra of complexes 5 and 6

show a typical symmetric stretching signal of C�C around 2100 cm-1.

2.2.2 Crystal structures

(�-PAnP)(AuCl)2 (1)

Two crystal forms of 1·0.5Et2O18b and 1·CH2Cl2 were obtained by slow diffusion of

Et2O and n-hexane into concentrated CH2Cl2 solutions of complex 1, respectively. The

molecular structures of 1·0.5Et2O and 1·CH2Cl2 are plotted in Figure 2.7 and 2.8,

respectively. Both forms show a typical linear coordination of gold(I) atoms ( av. P-Au-

Cl angle = 177.65° in 1·0.5Et2O; 174.13° in 1·CH2Cl2). Two P-Au-Cl groups in each

molecule of complex 1 are syn-oriented with intramolecular Au-P-P�-Au� torsion angles

of 3.2° (1·0.5Et2O) and 11.6° (1·CH2Cl2). The Au-P and Au-Cl bond lengths are typical

for phosphine gold(I) chlorides. Two gold atoms in each molecule are widely separated

by 9.154 Å (1·0.5Et2O) and 9.286 Å (1·CH2Cl2). To relieve the steric repulsion with the

19

phenyl rings, the anthracenyl rings are slightly curved toward the Au-Cl units. The

dihedral angles between the two lateral benzene rings are 23.0° and 22.0° for 1·0.5Et2O

(a) (b)

(a) (b)

Figure 2.7. (a) ORTEP diagram of a dimer of 1·0.5Et2O (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 1·0.5Et2O, viewed along the normal of the mean plane of the anthracenyl ring of C1B-C14B (for all diagrams, thermal ellipsoid = 50%)

Figure 2.8. (a) ORTEP diagram of a dimer of 1·CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 1·CH2Cl2, viewed along the normal of the mean plane of the anthracenyl ring of C1B-C14B (for all diagrams, thermal ellipsoid = 50%)

20

and 1·CH2Cl2, respectively. The space groups of the two crystal forms are the same and

interchangeable (P2(1)/n for 1·0.5Et2O and P2(1)/c for 1·CH2Cl2). Though molecules of

complex 1 in both crystal forms are packed in dimers with non-bonded solvent molecules

(Et2O or CH2Cl2) in crystal lattice, the extent of dimerization is different. In the Et2O-

containing form, two neighboring anthracenyl rings are parallel with each other (dihedral

angles between the mean planes of two anthracenyl rings are 0°) and partially overlapped

with each other with mean plane separations of 3.38 Å, which show a typical off-set

geometry of �-� stacking38 (Figure 2.7(b)). The intermolecular Au-Au distance of 4.449

Å is too long to indicate any Au-Au interaction. However, in the CH2Cl2-containing form,

both �-� and Au-Au interactions are present: �-� separation of 3.49 Å and intermolecular

Au-Au distance of 3.527 Å (Figure 2.8(a)). As a result of a shorter intermolecular Au-Au

seperation, the overlapping area of the two anthracenyl rings is larger in 1·CH2Cl2 than

that in 1·0.5Et2O. In both forms, the two adjacent P-Au-Cl units between two dimerized

molecules are in the staggered conformations with Cl-Au-Au�-Cl� torsion angles of 103.4°

(1·0.5Et2O) and 89.4° (1·CH2Cl2). Selected interatomic distances and angles of complex

1 in the two crystal forms are listed in Table 2.1.

1·0.5Et2O 1·CH2Cl2 Distances (Å) Au1-P1 2.2342(16) 2.2339(18) Au2-P2 2.2361(16) 2.2297(17) Au1-Cl1 2.2975(15) 2.3021(17) Au2-Cl2 2.3034(16) 2.2873(16) Au1···Au2 9.154 9.286 Angles (°) P1-Au1-Cl1 177.08(6) 173.65(7) P2-Au2-Cl2 178.22(6) 174.61(7)

Table 2.1. Selected interatomic distances and angles in 1·0.5Et2O and 1·CH2Cl2

21

(�-PAnP)(AuBr)2 (2)

Complex 2 also crystallizes in different forms in two solvent systems: 2·Et2O in

CH2Cl2/Et2O and 2·2CH2Cl2 in CH2Cl2/n-hexane. The crystal structures of 2·Et2O and

(a) (b)

(a) (b)

Figure 2.9. (a) ORTEP diagram of a dimer of 2·Et2O (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 2·Et2O, viewed along the normal of the mean plane of the anthracenyl ring of C1A-C14A (for all diagrams, thermal ellipsoid = 50%)

Figure 2.10. (a) ORTEP diagram of a dimer of 2·2CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 2·2CH2Cl2, viewed along the normal of the mean plane of the anthracenyl ring of C1A-C14A (for all diagrams, thermal ellipsoid = 50%)

22

2·2CH2Cl2 are shown in Figure 2.9 and 2.10, respectively. Gold(I) atoms in each form

show similar linear coordination geometry (av. P-Au-Br angle = 177.43° in 2·Et2O;

176.39° in 2·2CH2Cl2). Like that of complex 1, the molecule of complex 2 in each form

possesses two syn-oriented P-Au-Br groups with small intramolecular Au-P-P�-Au�

torsion angles of 3.5° (2·Et2O) and 2.4° (2·2CH2Cl2). The Au-P and Au-Br bond lengths

in both forms show no abnormity (see Table 2.2 for selected interatomic distances and

angles of complex 2). The intramolecular Au-Au separations are as wide as 9.091 Å

(2·Et2O) and 9.042 Å (2·2CH2Cl2). For the similar steric consideration to that of complex

1, the anthracenyl rings in complex 2 are also slightly curved toward the Au-Br units,

dihedral angles between the two lateral benzene rings being 24.2° (2·Et2O) and 24.5°

(2·2CH2Cl2). In crystal lattice, both 2·Et2O and 2·2CH2Cl2 are packed in dimers via only

off-set �-� stacking (�-� separation = 3.42 Å and 3.48 Å, respectively), solvents being

non-bonded. The two adjacent P-Au-Br units between two dimerized

molecules are in the staggered conformations with Br-Au-Au�-Br� torsion angles of

2·Et2O 2·2CH2Cl2 Distances (Å) Au1-P1 2.2345(14) 2.2313(16) Au2-P2 2.2245(13) 2.2356(18) Au1-Br1 2.3924(7) 2.3936(8) Au2-Br2 2.3902(6) 2.3974(8) Au1···Au2 9.091 9.042 Angles (°) P1-Au1-Br1 178.28(4) 175.42(5) P2-Au2-Br2 176.57(4) 177.37(5)

104.0° (2·Et2O) and 108.2° (2·2CH2Cl2), no Au-Au interaction (intermolecular Au-Au

distance = 4.519 Å (2·Et2O) and 4.620 Å (2·2CH2Cl2)) being present.

Table 2.2. Selected interatomic distances and angles in 2·Et2O and 2·2CH2Cl2

23

(�-PAnP)(AuI)2 (3)

The molecular structure of the iodide complex is similar to those of complexes 1 and 2.

Complex 3 crystallizes with one molecule of 3 and one solvent molecule of CH2Cl2 in the

asymmetric unit in solvent system of CH2Cl2/n-hexane. The gold atoms in 3·CH2Cl2 also

adopt linear coordination geometry with a smaller average P-Au-X angle of 171.14° than

those in complexes 1 and 2. The P-Au-X groups in one molecule of 3 are also syn-

oriented with a larger Au-P-P�-Au� torsion angle of 12.3° than those of complexes 1 and 2.

The Au-P and Au-I bond lengths (Table 2.3) compare favorably with those found in

other phosphine gold(I) iodides.28b-d, 29m The intramolecular Au-Au separation is 9.334 Å.

The anthracenyl rings are also slightly curved toward the Au-I units with a dihedral angle

of 16.1° between the two lateral benzene rings. 3·CH2Cl2 also forms dimers in solid state.

However, the packing geometry is different from that of complex 1 and 2. An ORTEP

drawing of a dimeric unit of 3 is shown in Figure 2.11(a). Two neighboring anthracenyl

rings are also parallel with each other with a negligible dihedral angle of 0.5° between

their mean planes. Instead of an off-set �-� stacking, a face-to-face �-� stacking

(staggered overlapping at the central benzene rings of anthracenyl groups) is found in

dimers of complex 3. The distance between the mean planes of two anthracenyl rings is

3.58 Å. A short intermolecular Au-Au contact of 3.518 Å found in the dimer of complex

3 is an evidence for weak Au-Au interactions. The two adjacent P-Au-I units between

two dimerized molecules are in the staggered conformations with an I-Au-Au�-I� torsion

angle of 99.1°.

24

Distances(Å) Angles(°) Au1-P1 2.251(3) P1-Au1-I1 174.54(9) Au2-P2 2.250(2) P2-Au2-I2 167.73(9) Au1-I1 2.5625(8) Au2-I2 2.5474(7) Au1···Au2 9.334

(�-PAnP)(AuNO3)2 (4)

The molecular structure of 4 is shown in Figure 2.12. Complex 4 crystallizes with one

molecule of 4 and half of solvent molecule of diethyl ether in the asymmetric unit in

solvent system of CH2Cl2/Et2O. One of the two nitrate groups (nitrogen atom N1, oxygen

atoms O1 and O2) is disordered over two locations with occupancies of 0.5 and 0.5. The

Table 2.3. Selected interatomic distances and angles in 3·CH2Cl2

(a) (b)

Figure 2.11. (a) ORTEP diagram of a dimer of 3·CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 3·CH2Cl2, viewed along the normal of the mean plane of the anthracenyl ring of C1B-C14B (for all diagrams, thermal ellipsoid = 50%)

25

selected bond lengths and angles of 4·0.5Et2O are listed in Table 2.4. The nitrate anions

coordinate to their respective gold atoms by only one of the three oxygen atoms with an

average Au-O distance of 2.13 Å, which is longer than that of some other reported gold

nitrate complexes such as (Me3P)Au(ONO2) (av. Au-O bond length = 2.094 Å),51

indicative of a weaker Au-O bonding in complex 4. Such a weaker bonding is also

(a)

(b) (c)

Figure 2.12. (a) ORTEP diagram of a monomer of 4·0.5Et2O (the disorder of one of the nitrate groups is shown by bonds of open lines and the dashed-open line indicates the Au-O interaction; for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) ORTEP diagram of a dimer of 4·0.5Et2O (for clarity, only half of positions of the disorder nitrate groups are shown); (c) �-� stacking geometry in 4·0.5Et2O, viewed along the normal of the mean plane of the anthracenyl ring of C1-C14 (for all diagrams, thermal ellipsoid = 50%)

26

Distances(Å) Angles(°) Au1-O1A 2.19(4) P1-Au1-O1A 162.5(10) Au1-O1B 2.11(2) P1-Au1-O1B 178.8(8) Au1-P1 2.208(2) P2-Au2-O4 177.0(3) Au1-O2A 2.43(3) O2A-N1A-O1A 108(3) Au2-O4 2.092(7) O2A-N1A-O3 130(2) Au2-P2 2.213(2) O1A-N1A-O3 122(3) N1A-O1A 1.210(10) O1B-N1B-O2B 115(2) N1A-O2A 1.205(10) O1B-N1B-O3 111(2) N1A-O3 1.212(10) O2B-N1B-O3 131(2) N1B-O1B 1.215(10) O5-N2-O4 121.1(11) N1B-O2B 1.216(10) O5-N2-O6 122.4(11) N1B-O3 1.220(10) O6-N2-O4 116.6(9) N2-O4 1.228(11) N2-O5 1.204(10) N2-O6 1.218(13) Au1···Au2 9.197

indicated by the fact that the N-O bonds connecting to the gold atoms ( N1A-O1A

1.210(10) Å; N1B-O1B 1.215(10) Å; N2-O4 1.228(11) Å) are not much longer than the

non-ligated N-O bonds (N1A-O2A 1.205(10) Å; N1A-O3 1.212(10) Å; N1B-O2B

1.216(10) Å; N1B-O3 1.220(10) Å; N2-O5 1.204(10) Å; N2-O6 1.218(13) Å). The

distance between Au1 and O2A is 2.43(3) Å, which is considered as a weak Au-O

interaction52 as it is significantly shorter than the sum of the van der Waals radii of gold

and oxygen (3.18 Å).53 The geometries at the gold centers are close to linear with an

average P-Au-O angle of 172.8°. The intramolecular Au-Au separation is 9.197 Å. The

two P-Au-O units attached to an anthracenyl ring are in a syn-orientation with a small

Au-P-P�-Au� torsion angle of 8.20°. The anthracenyl rings are slightly curved toward the

Au-O units with a dihedral angle of 15.0° between the two lateral benzene rings. The

Table 2.4. Selected interatomic distances and angles in 4·0.5Et2O

27

configuration at the nitrogen atoms is planar with O-N-O angles in the range of 108(3)-

131(2)°. Complex 4 is also packed in dimers with similar geometry to that of 3·CH2Cl2

(Figure 2.12(b) and (c)). A similar face-to-face �-� stacking is observed between two

neighboring anthacenyl rings. The dihedral angle between the mean planes of these two

rings is 0.7°. The �-� separation of 3.72 Å is wider than those of complexes 1-3, whereas

the intermolecular Au-Au distance of 3.375 Å is the shortest among complexes 1-4. The

two adjacent P-Au-O units between two dimerized molecules are in the staggered

conformations with O-Au-Au�-O� torsion angles of 93.9° (O1B-Au1-Au2A-O4A) and

76.4° (O1A-Au1-Au2A-O4A).

(�-PAnP)(AuC�CPh)2 (5)

Complex 5 crystallizes with one molecule of 5 and one solvent molecule of THF in the

asymmetric unit in solvent system of THF/n-hexane. The molecular structure of 5 is

shown in Figure 2.13. And the selected bond lengths and angles of 5·THF are listed in

Table 2.5. The C�C bond lengths of 1.193(9) Å and 1.178(9) Å are characteristic of

terminal acetylides. An average Au-P bond length of 2.2716 Å and an average Au-C

bond length of 1.993 Å are similar to those found in other phosphine gold(I) acetylides.27g,

i, 29f, 54 The geometry at the gold(I) centers is close to linearity with an average P-Au-C

angle of 170.2° and an average Au-C-C angle of 173.0°, which is indicative of the sp

hybridization in AuI and acetylenic carbon necessary for a rigid-rod molecule. The two P-

Au-C groups are in a syn-orientation with an Au-P-P�-Au� torsion angle of 10.1°. The

intramolecular Au-Au distance is 9.346 Å. The anthracenyl rings are slightly curved

toward the Au-C units with a dihedral angle of 19.6° between the two lateral benzene

rings. Complex 5 is packed in dimers via both �-� and Au-Au interactions. An off-set �-�

28

Distances (Å) Angles (°) Au1-P1 2.2765(15) P1-Au1-C1 170.1(2) Au2-P2 2.2667(15) P2-Au2-C3 170.2(2) Au1-C1 1.993(7) Au1-C1-C2 172.2(6) Au2-C3 1.993(6) Au2-C3-C4 173.3(7) C1-C2 1.193(9) C1-C2-C1E 177.8(8) C3-C4 1.178(9) C3-C4-C1F 177.6(8) Au1···Au2 9.346

stacking in 5·THF similar to those in complexes 1 and 2 is observed between two

neighboring anthacenyl rings. The dihedral angle between the mean planes of these two

rings is 2.2°. The �-� separation of 3.54 Å is slightly wider than those found in 1 and 2.

However, the �-� overlapping area in 5 is much larger than those in 1 and 2. This is due

to the fact that a much shorter intermolecular Au-Au contact of 3.259 Å makes the two

(a) (b)

Figure 2.13. (a) ORTEP diagram of a dimer of 5·THF (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) �-� stacking geometry in 5·THF, viewed along the normal of the mean plane of the anthracenyl ring of C5-C18 (for all diagrams, thermal ellipsoid = 50%)

Table 2.5. Selected interatomic distances and angles in 5·THF

29

anthracenyl rings get closer over the top of each other. The C-Au-Au�-C� torsion angles of

90.1° show apparently that two adjacent P-Au-C units between two dimerized molecules

are perpendicular with each other.

(�-PAnP)(AuC�CAn)2 (6)

Two independent molecules (6a and 6b) of very similar structures are found in the

crystals of 6·0.75CH2Cl2, which are obtained in solvent system of CH2Cl2/Et2O. The

molecular structure of 6a is shown in Figure 2.14(a). Some of the corresponding bond

lengths and angles are listed in Table 2.6. The C�C bond lengths of 1.167(14) Å and

1.165(15) Å are slightly shorter than those found in complex 5. The bond lengths of Au-P

(av. 2.279 Å) and Au-C (av. 1.990 Å) are similar to those found in 5. The geometry at the

gold(I) centers is close to linearity with an average P-Au-C angle of 175.4° and an

average Au-C-C angle of 173.7°. Unlike those of complexes 1-5, the two P-Au-C groups

of 6a are not in a syn-orientation. The Au-P-P�-Au� torsion angle is 119.2°. And the

intramolecular Au-Au distance of 8.864 Å is shorter than those found in complexes 1-5.

The anthracenyl ring of the PAnP moiety is curved with a dihedral angle of 26.6°

between the two lateral benzene rings, whereas the two anthracenyl rings connected to

the C�C bonds are almost planar (mean deviation: 0.0416 Å and 0.0752 Å). The packing

of molecules 6 (including both 6a and 6b, Figure 2.14(b)) looks much more complicated

than those observed in complexes 1-5. No apparent dimerization or oligomerization is

observed. There is no apparent face-to-face or off-set �-� stacking among all the

anthracenyl rings. And the shortest intermolecular Au-Au separation is found to be 6.72

Å, which is too long to indicate any Au-Au interaction. However, an investigation of the

p a c k i n g o f 6 a ( F i g u r e 2 . 1 4 ( c ) , m o l e c u l e s 6 b a r e o m i t t e d t o

30

(a) (b)

Figure 2.14. (a) ORTEP diagram of molecule 6a (thermal ellipsoid = 50%; for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted); (b) packing diagram of molecules 6a and 6b; (c) packing diagram of 6a showing a tetramer via edge-to-face �-� stacking among anthracenyl rings of A-F; (d) packing diagram of 6a showing the edge-to-face �-� stacking geometry of rings A-F

(c) (d)

31

Distances (Å) Angles (°) Au1-P1 2.284(2) P1-Au1-C15 175.0(4) Au2-P2 2.274(3) P2-Au2-C31 175.7(4) Au1-C15 1.989(10) Au1-C15-C16 173.8(11) Au2-C31 1.990(10) Au2-C31-C32 173.5(11) C15-C16 1.167(14) C15-C16-C17 176.6(13) C31-C32 1.165(15) C31-C32-C33 176.7(13) Au1···Au2 8.864

reduce the complexity of the diagram) reveals that molecules 6a are packed in tetramers

through cooperative intermolecular edge-to-face �-� stacking among the anthracenyl

rings. The edge-to-face �-� stacking exists among six anthracenyl rings A-F (C and F

from PAnP; A, B, D and E from 9-anthracenyl acetylide groups). By omitting all other

unrelated atoms, Figure 2.14(d) gives a clearer view of how these six rings interact with

each other. For the convenience of description, a vector is used to denote the edge-to-face

�-� interaction. For example, A�B denotes the interaction between the ‘edge’ of ring A

and the ‘face’ of ring B. Thus, the interactions of these six rings can be regarded as a

cycle of six vectors: A�B�C�D�E�F�A. For comparison with edge-to-face �-�

interactions between benzene rings, such interactions among A to F can be regarded as

between corresponding benzene rings of the anthracenyl groups. For example, A�B is

actually between one of the two lateral benzene rings of A and the central benzene ring of

B. The distance between the centroids of such two benzene rings of A and B (dA�B) is

4.799 Å. And the dihedral angle between the mean planes of such two benzene rings of A

and B (�A�B) is 84.5º. Other corresponding d and � are listed in Table 2.7. All these

parameters compare favorably with those reported for edge-to-face �-� interactions

between phenyl rings (30º<�<90º, 4.5Å<d<7Å).40 Therefore, the absence of Au-Au

Table 2.6. Selected interatomic distances and angles of 6a

32

interactions, face-to-face and off-set �-� interactions in complex 6 may be attributed to

the preference of the above cooperative edge-to-face �-� stacking.

Centroid-centroid distance d (Å)

Dihedral angle between mean planes of benzene rings � (º)

A�B 4.799 84.5 B�C 4.663 63.0 C�D 4.841 82.9 D�E 4.799 84.5 E�F 4.663 63.0 F�A 4.841 82.9

The structure data of complexes 1-6 show that the Au-P bond length is in an increasing

order of NO3- < Cl- � Br- < I- < RC�C-, in line with the trans influence series of these

ancillary ligands established on mononuclear PtII complexes.55 Complexes 1-5 are all

dimerized via �-� interactions with �-� separations in the range of 3.4-3.7 Å. Some of the

intermolecular parameters are summarized in Table 2.8 for comparison. The �-

overlapping areas and stacking geometries of the two neighboring anthracenyl rings are

quite different in these complexes. The area of �-overlapping is in a sequence of

1·0.5Et2O � 2·Et2O � 2·2CH2Cl2 < 3·CH2Cl2 � 4·0.5Et2O < 1·CH2Cl2

� 5·THF. Such a

sequence may indicate a similar order of strength of �-� interaction in them, since van der

Waals interaction may make an appreciable contribution to the magnitude of the �-�

interaction and it is roughly proportional to the area of �-overlapping.38 The geometry of

�-� stacking in 1·0.5Et2O, 1·CH2Cl2, 2·Et2O, 2·2CH2Cl2 and 5·THF is an offset stacking,

while in 3·CH2Cl2 and 4·0.5Et2O it is face-to-face stacking. Being electron-withdrawn

indirectly by AuI through phosphorus atoms, the anthracenyl ring (especially the central

Table 2.7. Edge-to-face �-� stacking parameters in complex 6

33

Crystals of (�-PAnP)(AuX)2

intermolecular Au-Au distance (Å)

�-� separation (Å)

�-� stacking geometry

�-overlapping area

X = Cl- (1·0.5Et2O) 4.449 3.38 off-set small

X = Cl- (1·CH2Cl2) 3.527 3.49 off-set large

X = Br- (2·Et2O) 4.519 3.42 off-set small

X = Br- (2·2CH2Cl2) 4.620 3.48 off-set small

X = I- (3) 3.518 3.58 face-to-face medium

X = NO3- (4) 3.375 3.72 face-to-face medium

X = PhC�C- (5) 3.259 3.54 off-set large

benzene ring which directly connects with two phosphorus atoms) becomes an electron

acceptor which is �-deficient. Therefore, according to Sanders’ model,38 both the above

geometry of stacking could be attractive. However, the reason that 3·CH2Cl2 and

4·0.5Et2O prefer a different stacking geometry from others is not clear. A possible factor

is crystal packing forces.

While literature studies have shown that analogous phosphine gold(I) complexes of

Ph3PAuX (X= halides28c, NO3-56) do not form any Au-Au interactions due to steric

repulsion caused by the bulky ligand PPh3, our results show that weak Au-Au interactions

take place in the PAnP-Au complexes of 1·CH2Cl2 (chloride), 3·CH2Cl2 (iodide) and

4·0.5Et2O (nitrate). This may indicate that attractive �-� interactions in these complexes

overcome the steric repulsions to make two intermolecular gold atoms be able to

approach each other. And this is in accordance with Onaka and coworkers’ conclusion

that most dimers of a series of monodentate arylphosphine gold(I) complexes R3PAuX (R

= m-H3CC6H4, p-H3CC6H4, m-F3CC6H4 , p-F3CC6H4 or 3, 5-(F3C)2C6H3; X = chloride,

Table 2.8. Parameters for comparison of Au-Au and �-� interactions in complexes 1-5

34

phenylthiolate or 4-pyridylthiolate) constructed by Au-Au interaction appeared to be

reinforced by �-� interaction.48c On the contrary, no Au-Au interaction is observed in

1·0.5Et2O, 2·Et2O and 2·2CH2Cl2. The absence of Au-Au interaction in these three forms

is not likely due to the electronic nature of the gold atoms, as the electron density of gold

atoms in them is comparable to that in the crystal forms of chloride (1·CH2Cl2) and iodide

(3·CH2Cl2). Neither can it be ascribed to temperature effect, since all single crystals were

grown at room temperature and structure analysis for all of them were carried out at the

same temperature (223K). Therefore, it is most probably due to the effect of solvent

molecules. Though all solvent molecules in all crystal forms of complexes 1-5 are non-

bonded, they play an important role in stabilizing the crystal lattice by filling spaces

properly. The presence of Au-Au interaction may depend on either the type of solvent

(comparing 1·0.5Et2O with 1·CH2Cl2) or the molar percentage content of solvent

(comparing 1·CH2Cl2 with 2·2CH2Cl2).

2.2.3 Electronic absorption and emission spectroscopy

The electronic absorption spectra of complexes 1-5 are very similar. The absorption

spectrum of complex 4 is shown in Figure 2.15 (for complexes 1, 2, 3 and 5, see

Appendices). It displays two sets of absorption bands. One set of intense and vibronic

structured absorption bands ranging from 350 nm to 470 nm is assigned to intraligand

1�� �* transition of the anthracenyl moieties, while the other set of strong absorption

bands at higher energy region (235-300 nm) is assigned to the 1�� �* transition within

the phenyl rings of PPh2 groups (probably plus the transition within anthracenyl groups

between S0 and some excited state with higher energy level than that of �*). Such

35

assignments are based on previous spectroscopic study of the free ligand PAnP, which

show similar absorption bands.18

The absorption spectrum of complex 6 (Figure 2.16) shows a slightly different profile

from those of complex 1-5. The absorption bands ranging from 350 nm to 460 nm are

more vibronic structured and intense than those of complexes 1-5. Such a difference is

300 400 500 6000

20000

40000

60000

80000

100000

Ext

inct

ion

coef

ficie

nt(M

-1cm

-1)

Wavelength(nm)

Figure 2.15. UV-visible absorption spectrum of complex 4 in CH2Cl2 at room temperature

300 400 500 6000

50000

100000

150000

200000

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

300 400 500 6000

50000

100000

150000

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

Figure 2.16. UV-visible absorption spectrum of complex 6 in CH2Cl2 at room temperature

Figure 2.17. UV-visible absorption spectrum of AnC�CSiMe3 in CH2Cl2 at room temperature

36

caused by the absorption of the anthracenyl acetylide moieties in complex 6, as those

moieties are absent in other complexes. These absorption bands are attributable to the

mixing of 1���* transition of the anthracenyl moiety of PAnP with the 1���* transition

of the anthracenyl acetylide moieties, as a similar vibronic absorption band ranging from

330 nm to 420 nm is observed in the absorption spectrum of the free ancillary ligand 9-

trimethylsilylethynylanthracene (AnC�CSiMe3) (Figure 2.17). Therefore, the higher

intensity of these absorption bands in complex 6 is also reasonable, as it is the sum of

absorbencies of two such transitions. For example, the extinction coefficient of complex

6 at 421 nm is 42750 M·cm-1, while those of complexes 1-5 and AnC�CSiMe3 are less

than 20000 M·cm-1. The high energy absorption bands (235 nm to 300 nm) of both

complex 6 and AnC�CSiMe3 (extinction coefficients at about 270 nm are larger than

150000 M·cm-1) are also much more intense than those of complexes 1-5 (extinction

coefficients at about 270 nm are less than 100000 M·cm-1). Therefore, such high energy

absorption bands of complexes 1-6 are not only due to the 1���* transition within the

phenyl rings of PPh2 groups but also the transition within anthracenyl groups between S0

and some excited state with higher energy level than that of �*. The photophysical data of

these complexes are listed in Table 2.9.

Complexes 1-6 are all emissive at room temperature in CH2Cl2 solution. The emission

spectra of complexes 1-5 are similar. The emission spectrum of complex 3 in CH2Cl2

solution is shown in Figure 2.18 (for complexes 1, 2, 4 and 5, see Appendices). The

spectrum shows a broad non-structured emission band (excited at 390 nm) between 450

nm and 600 nm with maximum at 486 nm. Therefore such emission band is assigned to

the intraligand 1(��*) transition, as the Stokes shift is small between absorption and

37

absorption emission (in CH2Cl2) emission (solid state) compound �max/nm

(�/M-1cm-1) �max /nm excited at/nm �max/nm excited at/nm

1�0.5Et2O 490

(µ-PAnP)(AuCl)2 (1)

272(66290), 391(10210), 417(14590), 442(15340)

482 390

1�CH2Cl2 490

410

2�Et2O 514

(µ-PanP)(AuBr)2 (2)

272(79000), 391(12090), 418(17530), 442(18040)

480 390

2�2CH2Cl2 510

400

(µ-PanP)(AuI)2

(3)

273(63390), 393(9670), 420(15250), 444(16100)

486 390 529 390

(µ-PanP)(AuNO3)2 (4)

273(88030), 392(13660), 420(19320), 444(20290)

483 390 511 350

(µ-PanP)(AuC�CPh)2

(5)

271(79950), 390(7520), 416(10600), 440(10790)

478 390 508 410

(µ-PanP)(AuC�CAn)2

(6)

266(197770), 376(19630), 397(36020), 421(42710), 438(16130)

412(sh), 433, 453,

474(sh)

350 486, 535, 600 300

AnC�CSiMe3

264(169720), 350(4610), 368(10940), 387(19420), 410(19920)

417, 441, 464,

498(sh)

350

Table 2.9. Photophysical data of complexes 1-6 and AnC�CSiMe3

38

emission. However, the emission spectrum of complex 6 is different (Figure 2.19). It

shows a broad and poorly structured emission band between 400 and 550 nm with

maxima at 433 and 453 nm. Like its absorption spectrum, such a structured emission

band is assigned to the mixing of 1(��*) transition of the anthracenyl rings of PAnP with

the 1(��*) transition of the anthracenyl acetylide moieties, as a vibronic emission band

ranging from 400 to 520 nm (with maxima at 417, 441 and 464 nm) is observed in the

400 450 500 550 6000

50

100

150

200

250

300

Inte

nsity

(a.u

.)

Wavelength (nm)

Figure 2.18. Emission spectrum of complex 3 in CH2Cl2 at room temperature excited at 390 nm

400 500 6000

200

400

600

800

Inte

nsity

(a.u

.)

Wavelength (nm)

400 450 500 550 6000

200

400

600

800In

tens

ity (a

.u.)

Wavelength (nm)

Figure 2.19. Emission spectrum of complex 6 in CH2Cl2 at room temperature excited at 350 nm

Figure 2.20. Emission spectrum of AnC�CSiMe3 in CH2Cl2 at room temperature excited at 350 nm

39

emission spectrum of the free ancillary ligand AnC�CSiMe3 (Figure 2.20). Similar

vibronic emission bands were observed in other alkenyl57 or alkynyl58 anthracenes.

The fluorescence of complexes 1-6 is also observed in solid state. 1�0.5Et2O and

1�CH2Cl2 display similar non-vibronic emission bands in the range of 450-650 nm

(Figure 2.21) with maxima at the same position of 490 nm, which is red shifted from that

observed in CH2Cl2 solution (482 nm). These emission are assigned to the similar ��*

transition of the anthracenyl group. The red shift may be due to the suggestion that the �-

� stacking of the anthracenyl rings is present only in solid state but not in solution. The

similarity of the emission from the two different crystal forms may indicate that neither

the appearance of Au-Au interactions nor the area of �-� overlapping has substantial

effect on the energy gap between the ground and excited states of the molecule. Such a

similarity is also observed for the two crystal forms of complex 2. The profiles of the

500 600 700 8000

300

600

900

CH2Cl

2.10.5Et

2O.1

Inte

nsity

(a.u

.)

Wavelength (nm)

Figure 2.21. Emission spectrum of complex 1 in solid state at room temperature excited at 410 nm

40

solid state emission spectra of complexes 4 and 5 are similar to those of complexes 1 and

2, showing slightly different degree of red shift from their emissions in solution (see

Appendices for the solid state emission spectra of complexes 2, 4 and 5).

Unlike those of complex 1, the solid state emission spectrum of 3 shows dual emissions:

one with maximum at 529 nm and the other one broadly located between 550 and 650 nm

(Figure 2.22). According to Che and co-workers’ spectroscopic and computational study

of some polynuclear gold(I) halides containing bridging phosphine ligands, the HOMO of

these gold halides modified by Au-Au interaction have increased halide contribution

from chloride to iodide.29m Therefore, the emission of lower energy in complex 3 is

assigned to ligand (I-) to ligand (�* of PAnP) charge transfer (LLCT) transition. And the

emission of higher energy is assigned to the intraligand 1(��*) transition of the

anthracenyl group. Like the case for complexes 1, 2, 4 and 5, such 1(��*) transition

emission of complex 3 is red-shifted from 486 to 529 nm, on going from in solution to in

solid state. The solid state emission band of complex 6 is poorly vibronic structured

500 600 700 8000

20

40

60

80

100

Inte

nsity

(a.u

.)

Wavelength (nm)

Figure 2.22. Emission spectrum of complex 3 in solid state at room temperature excited at 390 nm

400 500 600 700 8000

100

200

300

Inte

nsity

(a.u

.)

Wavelength(nm)

Figure 2.23. Emission spectrum of complex 6 in solid state at room temperature excited at 300 nm

41

(Figure 2.23) like that in solution, which is attributed to a similar mixing of 1(��*)

transition of the anthracenyl rings of PAnP with the 1(��*) transition of the anthracenyl

acetylide moieties.

To know whether complexes 1-5 form dimers in solution like in solid state, the effect of

concentration on their 1H-NMR and UV-visible absorption spectra was investigated.

However, none of these spectra was found to be concentration dependent, which rules out

the presence of any degree of ground state aggregation of these complexes in solution.60

Though their emission spectra all show a slight red-shift upon concentration increase, this

may not be related to any excimer61 emission but to the self absorption at the high energy

part of the emission bands. This suggestion is based on the fact that there is partial

overlapping between absorption and emission spectra and such a red-shift is accompanied

by a drastic quenching of the fluorescence.

2.3 Conclusions

In this study, the crystal structure analysis of a series of phosphine gold(I) complexes 1-

5 showed that molecules in crystals of 1·CH2Cl2, 3·CH2Cl2, 4·0.5Et2O and 5·THF formed

dimers in solid states via both Au-Au and �-� interactions, whereas those in 1·0.5Et2O,

2·Et2O and 2·2CH2Cl2 dimerized only through the latter. The results suggest that solvent

molecules in the crystals play an important role in controlling the appearance of Au-Au

interactions. Complex 6 does not form similar dimers like 1-5. Intermolecular edge-to-

face �-� interactions were observed in 6·0.75CH2Cl2 to dominate over Au-Au interactions,

face-to-face and off-set �-� interactions. All these complexes showed strong ligand-

centered fluorescence upon photoexcitation in both solution and solid state at room

temperature.

42

2.4 Experimental section

General methods All reactions were carried out using standard Schlenck techniques.

AuBr3, AuI3, AgNO3 and PhC�CH purchased from Aldrich and KAuCl4.xH2O obtained

from Oxkem were used without further purification. All solvents used for syntheses and

spectroscopic measurements were purified according to the literature methods. The

ligand PAnP, complexes 1 and 2 were prepared according to previous methods,18 as was

ligand 9-trimethylsilylethynylanthracene (AnC�CSiMe3).62

(�-PAnP)(AuI)2 (3): 1.05 g (1.82 mmol) of AuI3 and 0.993 g (1.82 mmol) of PAnP were

added into 40 ml of methanol. After being stirred for 2 hours in absence of light, the

reaction mixture was filtered by suction and the solid was washed with methanol and then

diethylether. The solid was recrystallized from CH2Cl2-n-hexane to give yellow

crystalline material, which was subsequently dried in vacuum. Yield: 0.860 g (79%).

Anal. Calcd for C38H28Au2I2 P2·0.5CH2Cl2: C, 37.4; H, 2.4. Found: C, 37.4; H, 2.4. 1H-

NMR (300 MHz, CDCl3, /ppm): 8.26-8.23 (m, 4H, H1, 4, 5, 8 of anthracenyl ring), 7.71-

7.63 and 7.55-7.42 (m, 20H, Ph), 7.14-7.10 (m, 4H, H2, 3, 6, 7 of anthracenyl ring).

31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 32.87 (s). ESI-MS (m/z, assignment):

1067.2 [M − I]+. Single crystals of 3·CH2Cl2 for x-ray diffraction analysis were grown by

slow diffusion of n-hexane into a concentrated CH2Cl2 solution of 3.

(�-PAnP)(AuC�CPh)2 (5): 0.1 ml (0.912 mmol) of PhC�CH was added into 40 ml of

methanolic solution of 0.2 g (3.57 mmol) of potassium hydroxide. 0.200 g (0.198 mmol)

of 1 was then added into this solution to form a yellow suspension. After being stirred

overnight, the reaction mixture became an orange suspension. The orange solid was

collected by filtration and washed with methanol. The solid was then recrystallized from

43

CH2Cl2-Et2O to give an orange crystalline solid, which was subsequently dried in

vacuum. Yield: 0.173 g (76%). Anal. Calcd for C54H38Au2P2·0.5CH2Cl2: C, 55.2; H, 3.3.

Found: C, 55.6; H, 3.5. 1H-NMR (300 MHz, CDCl3, /ppm): 8.30-8.27 (m, 4H, H1, 4, 5, 8

of anthracenyl ring), 7.70-7.63 and 7.52-7.41 (m, 20H, Ph of PAnP), 7.23-7.18 (m, 5H,

Ph of -C�CPh), 7.13-7.10 (m, 4H, H2, 3, 6, 7 of anthracenyl ring). 31P{1H}-NMR (121.5

MHz, CDCl3, /ppm): 36.52 (s). IR (KBr, �(C�C)/cm-1): 2110 (br, w). ESI-MS (m/z,

assignment): 1339.1 [M + Au]+. Single crystals of 5·THF for x-ray diffraction analysis

were grown by slow diffusion of n-hexane into a concentrated THF solution of 5.

(�-PAnP)(AuC�CAn)2 (6): This compound was prepared in a manner similar to the

preparation of 5 except that PhC�CH was replaced by AnC�CSiMe3. Yield: 80%. Anal.

Calcd for C70H46Au2P2: C, 62.6; H, 3.5. Found: C, 62.0; H, 3.5. 1H-NMR (300 MHz,

CDCl3, /ppm): 8.82 (d, 4H, H1, 8 of anthracenyl ring of -C�CAn moiety), 8.42-8.39 (m,

4H, H1, 4, 5, 8 of anthracenyl ring of PAnP), 8.29 (s, 2H, H10 of anthracenyl ring of -

C�CAn moiety), 7.95 (d, 4H, H4, 5 of anthracenyl ring of -C�CAn moiety), 7.81-7.74 (m,

8H, H2, 3, 6, 7 of anthracenyl ring of -C�CAn moiety), 7.51-7.41 (m, 20H, Ph), 7.21-7.18

(m, 4H, H2, 3, 6, 7 of anthracenyl ring of PAnP). 31P{1H}-NMR (121.5 MHz, CDCl3,

/ppm): 36.77 (s). IR (KBr, �(C�C)/cm-1): 2091 (br, w). ESI-MS (m/z, assignment):

1539.1 [M + Au]+. Single crystals of 6·0.75CH2Cl2 for x-ray diffraction analysis were

grown by slow diffusion of diethyl ether into a concentrated CH2Cl2 solution of 6.

44

Chapter 3

First Examples of AuI-X-AgI Halonium Cations

45

3.1 Introduction

Silver(I) ion has strong affinity for soft halides. This property has long been harnessed

to remove the poor leaving halide ligand from a metal complex [M-X�]n+ (X� = Cl-, Br-, I-)

(equation 3.1, Y = anion).63

The stability and spontaneous precipitation of AgX� from the solution drive the

equilibrium toward the complex [M](n+1)+Y- which would react readily with an incoming

ligand.63 This simple synthetic strategy has been used to generate the (R3PAu)+ ion from

R3PAuCl (R = aryl or alkyl).64 The ion, a powerful aurating agent, has been used

extensively in synthesizing metal clusters, especially polygold(I) complexes.26l, 32, 65 An

example related to the present study is the formation of the novel [digold(I)]halonium

cations [(R3PAu)2X�]Y (Y = ClO4-,66 BF4

-,67a SbF6-67b, c) from the coordination of

(R3PAu)+ to the halide in R3PAuX�. Interestingly, recent studies showed that when SbF6-

is the counterion, the halonium ion would dimerize into [(Ph3PAu)2X�]22+ via aurophilic

attractions (Scheme 3.1).67b, c However, there are notable exceptions where silver

halides are found incorporated into the final clusters,68 i.e., [(p-

[M-X�]n+ + AgY [M](n+1)+Y- + AgX� (3.1)

AuCl

AuPh3P PPh3

Au

Cl

Au

Ph3P

Ph3P

Ph3PAu

ClAu

PPh3

2

+

2+

Scheme 3.1. Dimerization of [(Ph3PAu)2Cl]+ into [(Ph3PAu)2Cl]22+

46

tol3P)12Au18Ag20Cl14],68a and interestingly, both AgCl and (Ph3PAu)+ ions, produced

from the reaction of AgNO3 with Ph3PAuCl, are assembled in the cluster [Pt3(�3-

S)(AuPPh3)(�3-AgCl)(�-Ph2PCH2PPh2)3]+.68c Usón et al.69 demonstrated that the

reactions between organoplatinum halides and AgI ion give rise to complexes which

contain [Pt-X-Ag] linkage (X = Cl, Br). Remarkably, the structures of the complexes

implicate the existence of Pt�Ag bonding (Figure 3.1).

3.2 Objectives

Intrigued by the recent discovery of the novel dimerization of [(R3PAu)2X�] (X� = Cl or

Br) into the tetranuclear complexes [(Ph3PAu)2X�]22+,67b, c we attempted to apply this

strategy to our gold(I) phosphine system of (�-PAnP)(AuX)2 (X = Cl, (1); = Br, (2)) to

see whether (i) replacement of a monodentate phosphine with a bidentate one would give

a polymeric analogue and (ii) introduction of a large aromatic unit (anthracene) into the

ligand would give rise to any interesting 3-D structure via �-� interaction. Surprisingly,

treatment of the same salt AgSbF6 with our system led to the discovery of a new reaction

between AgI and phosphinegold(I) halides: instead of precipitating AgX, the reactions of

Pt

F

F

F

F

F

F

F

F

F

F

Cl

AgAg

Cl

Pt

F

F

F

F

F

F

F

F

F

F

Cl

Cl

2-

Figure 3.1. An example of [Pt-X-Ag] linkage69a

47

(�-PAnP)(AuX)2 with 1/2 mol equivalent of AgSbF6 gave rise to unprecedented AuI-X-

AgI halonium cations (Scheme 3.2).

3.3 Results and discussion

While reacting 1 and 2 with 2 mol equivalent of AgSbF6 leads to spontaneous

precipitation of AgX and formation of [(�-PAnP)Au2]2+ ion, slow diffusions between a

CH2Cl2 solution of (�-PAnP)(AuX)2 and a THF solution of 1/2 mol equivalent of AgSbF6

give yellow crystals of {[(�-PAnP)(AuX)2]2Ag}+SbF6-�2CH2Cl2 (X = Cl, 7�2CH2Cl2; X =

Br, 8�2CH2Cl2) as products. Both compounds crystallize in the tetragonal space group

I4/m. X-ray crystal analysis revealed that 7 (Figure 3.1) and 8 (Figure 3.2) are

isostructural, being composed of helical coordination polymers of (�-PAnP)(AuX)2 and

AgI ions. The SbF6- ions have no contact with the polymer chains. As is described in

Chapter 2, the anthracenyl rings in 1 and 2 are slightly curved toward the Au-X units to

relieve the steric repulsion with the phenyl rings and the dihedral angels between the two

lateral benzene rings are 23.0º and 24.2º for 1 and 2, respectively. Notably, the (�-

PAnP)(AuX)2 molecules undergo pronounced conformational changes in forming

compounds 7 and 8: the anthracenyl rings are slightly curved away from the Au atoms,

and the P-Au-X units are tilted toward one end of the anthracenyl ring (Figure 3.1b and

Figure 3.2b). The dihedral angles between the lateral benzene rings in 7 and 8 are 18.8°

2 (�-PAnP)(AuX)2THF/CH2Cl2

AgSbF6 {[(�-PAnP)(AuX)2]2Ag}+SbF6-

X = Cl (1) = Br (2)

X = Cl (7) = Br (8)Scheme 3.2. Synthesis of Au-X-Ag halonium cations

48

Figure 3.1. (a) ORTEP drawing of 7·2CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms, solvent molecules and anions are omitted); (b) Complex 7 viewed along c-axis (all phenyl rings are not shown); (c) Diagram showing the AgAu4Cl4 dodecahedron; the solid lines indicate the bonding interactions and the broken lines show the faces of the dodecahedron.

(c)

(a)

(b)

49

(a)

(c)

(b)

Figure 3.2. (a) ORTEP drawing of 8·2CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms, solvent molecules and anions are omitted); (b) Complex 8 viewed along c-axis (all phenyl rings are not shown); (c) Diagram showing the AgAu4Br4 dodecahedron; the solid lines indicate the bonding interactions and the broken lines show the faces of the dodecahedron.

50

and 17.9°, respectively. Because of the distortion, the two P-Au-X units are drawn closer

and the Au-Au distances are shortened to 7.737 and 7.768 Å in 7 and 8, respectively

(compared to 9.154 and 9.091 Å in 1 and 2, respectively). The large structural changes

suggest that the anthracenyl backbone of the ligand is highly flexible. The conformational

changes may facilitate �-� interactions between two (�-PAnP)(AuX)2 molecules whose

anthracenyl rings overlap partially with separations typical for aromatic �-� stacking

(3.627 Å (7) and 3.618 Å (8)).38 Intriguingly, the Au and X atoms of four neighboring (�-

PAnP)(AuX)2 molecules constitute the vertexes of a distorted deltahedral dodecahedron

(Figure 3.1c and Figure 3.2c). Encapsulated at the center of the polyhedron is a silver(I)

ion. Because of the different Au-X distances, the symmetry of the dodecahedron

degenerates from the maximum D2d to S4. The Au4X4 dodecahedron can be also called

bisdiphenoids as it comprises two interpenetrating Au4 and X4 tetrahedra. The four

halides coordinate weakly to the central AgI ion, showing long Ag-X bond distances (Ag-

Cl = 2.624(2) Å, Ag-Br = 2.7137(1) Å). The compounds feature the first examples of

(AuI-X)4AgI halonium ions which are nonclassical as the halides bear a fractional formal

charge of +1/4. The AgX4 tetrahedra are distorted with Cl-Ag-Cl angles of 115.00(5)°

and 98.90(9)° and Br-Ag-Br angles of 114.18(3)° and 100.42(5)°. On the other hand, the

distortion in the AgAu4 tetrahedra is more severe: the Au-Ag-Au angles in 7 and 8 are

126.385(9)°, 79.2569(2)° and 127.168(1)°, 77.977(2)°, respectively. The shortest Au-Au

distances in the dodecahedra, 4.105 Å (7) and 4.115 Å (8), are too long for aurophilic

interactions. The Au-X bonds (X = Cl, 2.313(2) Å; X = Br, 2.4171(1) Å) are basically

unaffected by the Ag-X coordination as they are only slightly longer than the

corresponding ones in 1 (2.2975(2) Å) and 2 (2.3924(7) Å). As the coordinated halides

51

are known as poor electron donors and AgI ion as a strong electron acceptor, the

halonium ions can be regarded as strong Lewis acid and weak Lewis base adducts.70

While the Au-P bonds of 7 and 8 (2.241(2) Å) have the same length, the Au-X and Ag-X

bonds are elongated significantly as X is changed from Cl to Br (Au-Cl = 2.313(2) Å,

Au-Br = 2.4171(1) Å, Ag-Cl = 2.624(2) Å, Ag-Br = 2.7137(1) Å). Surprisingly the Au-

Ag distance does not show a proportional increase: the unusually acute Au-Cl-Ag angle

of 81.08(7)° leads to the Au-Ag separation of 3.2180(4) Å in 7, and further compressed

Au-Br-Au of 79.04(4)° in 8 keeps a very similar Au-Ag of 3.2701(5) Å. Notably,

exceedingly small Pt-X-Ag angles are observed in {[(C6F5)2Pt-(�-Cl)2Ag]}22-

(65.9(2)°)69a and [(L)Pt(�-Br)Ag(PPh3)] (L = (Ph3P)(C6C15)Br) (70.6(1)°)69b which are

crucial in fostering Pt-Ag bonding. It is therefore believed that AuI-AgI metallophilic

interactions may play a role in stabilizing the halonium complexes. Closed-shell

interactions are responsible for the assembling of heavy d10 metal complexes in solid

state.27p, 51, 71 Although the Au-Ag distances in 7 and 8 are on the long end of the reported

AuI-AgI bond distance (2.8-3.3 Å),72 they are shorter than the sum of the van der Waals

radii of the metals (3.4 Å)53 and lie within the range of Au-Ag bond distances proposed

by theoretical calculations.72e Another structural feature lending support to the existence

of Au-Ag interactions is the bending of the P-Au-X units toward the central AgI ion,

illustrated by the fact that the P-Au-X angle in the halonium ions (X = Cl, 174.98(5)°; X

= Br, 173.60(9)°) are smaller than the corresponding ones in 1 (177.65(6)°) and 2

(177.43(4)°).

3.4 Conclusions

52

On the basis of these structural features, the halonium cations are believed to be

stabilized by the collective actions of Ag-X and Au-Ag and �-� interactions. This could

be the reason the formation of the halonium cations is favored over that of halide

abstraction. The robustness of the polymers is suggested by the insolubility of 7 and 8 in

most of the organic solvents except DMSO. The 31P{1H}-NMR spectra of 7 and 8

measured in DMSO-d6, which show a singlet at 26.85 and 28.82, respectively, are

identical to those of 1 and 2. In addition, the halide abstraction could be disfavored by the

low AgI/X ratio of 1/4 in the reactions as the Lewis acidity of AgI ion is expected to be

attenuated by the coordination of four halide ions.

Preliminary investigations of the effect of phopshines and anions on the structures and

stability of the halonium cations were also carried out. Unfortunately, no other

phosphines (PPh3, PPh2Me, Ph2PCH2PPh2) or other anions (CF3SO3-, ClO4

-, PF6-) were

found to give analogous halonium cations (either the target crystals formed are not of

sufficient quality for x-ray diffraction analysis, such as the cases for PPh3 and PPh2Me, or

salts AgX were formed and precipitated rapidly.).

3.5 Experimental section

Materials All solvents used for synthesized and crystallization were purified according

to the reported procedure. AgSbF6 was purchased from Aldrich.

{[(�-PAnP)(AuCl)2]2Ag}+SbF6- (7): 0.034 g of AgSbF6 (0.10 mmol) and 0.200 g of 1

(0.20 mmol) were dissolved in 25 ml of THF and 25 ml of CH2Cl2, respectively. The

THF solution was layered on the CH2Cl2 solution in a test tube and slow diffusion of the

two solutions afforded yellow crystals of the product at the interface after three days. The

product was dried in vacuum at room temperature in absence of light for 5 hours. Yield:

53

0.1g (43%) 1H-NMR (300 MHz, DMSO-d6, /ppm): 8.12-8.09 (m, 4H, H1, H4, H5 and H8

of anthracenyl ring), 7.81-7.75 and 7.59-7.52 (m, 20H, Ph), 7.24-7.20 (m, 4H, H2, H3, H6

and H7 of anthracenyl ring). 31P{1H}-NMR (121.5 MHz, DMSO-d6, /ppm): 26.85 (s).

Anal Calcd for C76H56Au4Cl4P4AgSbF6: C 38.57, H 2.39; Found: C 38.85, H 2.73. FAB-

MS: m/z = 975.0 [Au2(PAnP)Cl]+.

{[(�-PAnP)(AuBr)2]2Ag}+SbF6- (8): 0.0180 g of AgSbF6 (0.053 mmol) and 0.115 g of 2

(0.105 mmol) were dissolved in 10ml THF and 10 ml CH2Cl2, respectively. The THF

solution was layered on the CH2Cl2 solution in a test tube and slow diffusion of the

solutions afforded yellow crystals of the product after 3 days. The product was dried in

vacuum at room temperature in absence of light for 5 hours. Yield: 0.06 g (45%). 1H-

NMR (300 MHz, DMSO-d6, /ppm): 8.13-8.09 (m, 4H, H1, H4, H5 and H8 of anthracenyl

ring), 7.82-7.75 and 7.60-7.53 (m, 20H, Ph), 7.24-7.21 (m, 4H, H2, H3, H6 and H7 of

anthracenyl ring). 31P{1H}-NMR (121.5 MHz, DMSO-d6, /ppm): 28.82. Anal Calcd for

C76H56Au4Br4P4AgSbF6: C 35.86, H 2.20; Found: C 35.65, H 2.16. FAB-MS: m/z =

1020.9 [Au2(PAnP)Br]+.

54

Chapter 4

Systhesis, Structures and Electronic Spectroscopy of d10 Metal

Complexes with 9, 10-Anthracenedithiol Ligand

55

4.1 Introduction

d10 (CuI, AgI, AuI) metal thiolate complexes keep attracting considerable attention

because of their structural diversity,73-75 rich photophysics and photochemistry,73a-e,

74a,b,75a-c,76 and interesting biomedical activity.77 The novel structural and photophysical

properties of these complexes are often related to the following two facts. First, as sulfur

is an electron rich donor atom, thilolates have a strong tendency to act as bridging ligands

with bridging modes of �2-, �3- and �4-. Second, congeners of AuI, AgI and CuI are likely

to form weak attractions (d10-d10 metal-metal interactions) between metal centers. With

the aid of a bidentate phosphine ligand like dppm (1, 2-bis(diphenylphosphino)methane)

or a monodentate phosphine like PPh3, these complexes have been extensively reported

to form polynuclear structures such as [M4(�2-dppm)4(�4-S)]X2 (M = Cu, X = PF6-; M =

Ag, X = OTf-, triflate),73b, 74a [Ag6(�2-dppm)4(�3-SC6H4Me-p)4](PF6)2,74b [Au12(�2-

dppm)6(�3-S)4](PF6)475a and [(PPh3Au)4(�4-S)](OTf)2,75h despite that there seems no

regulation or predictability on the consequence of substituents on S atoms on the

nuclearity of corresponding thiolate complexes. The sulfur atom has been found to play

an important role in the luminescent behaviors of these complexes, with ligand(S)-metal

charge-transfer transition emissions (LMCT) often observed.73c, d, 74a, 75a, b, 76

Recently, our group has investigated the coordination chemistry of a dithiolate ligand: 1,

8-naphthalenedithiolate (NS22-, Figure 4.1).73c Under different conditions, NS2

2- reacts

with [Cu2(�2-dppm)2(CH3CN)2](PF6)2 to form two different structures of CuI dithiolates:

a tetranuclear complex [Cu4(�2-dppm)3(�2-�2-NS2)(�2-�4-NS2)] (Figure 4.2) and a

pentanuclear complex [Cu5(�2-dppm)4(�3-�3-NS2)2](PF6) (Figure 4.3). Both complexes

56

display dual emissions at 480 and 620 nm which arise from ligand-centered n�* and

ligand-metal charge-transfer excited states, respectively.

4.2 Objectives

As is mentioned in Chapter 1, the objective of this part of work was to investigate the

coordination chemistry of 9, 10-anthracenedithiol (H2SAnS, Figure 1.5, SAnS2- denotes

the corresponding dithiolate anion upon deprotonation) with d10 metals. While H2SAnS

was first prepared in 1983,78 to our knowledge, the coordination chemistry of this ligand

S S

Figure 4.1. Structure of 1, 8-naphthalenedithiolate (NS2

2-)

S S

Cu Cu

Cu Cu

PPh2Ph2P

Ph2P

Ph2P

S

SPh2P PPh2

Figure 4.2. Tetranuclear structure of [Cu4(�2-dppm)3(�2-�2-NS2)(�2-�4-NS2)]

S S

S

S

Cu

CuCu

CuCu

PPh2Ph2P

PPh2

PPh2

PPh2Ph2P

Ph2P

Ph2P

+

Figure 4.3. Pentanuclear structure of [Cu5(�2-dppm)4(�3-�3-NS2)2]+

57

remains to be studied. The anthracene unit in H2SAnS, like that in PAnP, is expected to

play an important role in constructing the structures of the complexes.

4.3 Results and discussion

4.3.1 Synthesis and crystal structures

The synthesis route for the ligand and complexes 9-11 is shown in Scheme 4.1. The

ligand H2SAnS was prepared according to literature method.78c Being exposed to air, the

ligand turned from yellow to red gradually, indicating oxidation of the sulfur atoms.

Therefore the ligand was stored under nitrogen and used for further reactions shortly after

preparation. The reaction between SAnS2- and the copper starting material [Cu2(�2-

dppm)2(CH3CN)2](PF6)2 was operated with similar procedures to those of Yam.76 The

only difference was that the molar ratio of [Cu2(�2-dppm)2(CH3CN)2](PF6)2 to sulfur

element was changed from 3/4 to 1/1. Instead of a �3-bridging mode, the sulfur atoms of

SAnS2- show a �2-bridging mode to form a bis-dinuclear metal complex [(Cu2(�2-

dppm)2)2(�2-�2-SAnS)](PF6)2 (9). The silver analogue [(Ag2(�2-dppm)2)2(�2-�2-

SAnS)](ClO4)2 (10) was prepared with the same procedures just by changing the metal

starting material to [Ag2(�2-dppm)2](ClO4)2 . Slow diffusions of diethyl ether vapor into

concentrated CH3CN solutions of these complexes gave red single crystals of

9·3CH3CN·Et2O·0.5H2O and 10·4.6CH3CN respectively, which were structurally

characterized by x-ray diffraction analysis. Their molecular structures are shown in

Figure 4.4, and some of the selected interatomic distances and angles are listed in Table

4.1. Both complexes crystallize in the monoclinic space group P21/n. Each molecule of 9

or 10 has an invertion center at the centroid of the anthracenyl ring. In both 9 and 10, the

58

OO H3CO P

S

SS

P

S

OCH3 SS

SHHS SNaNaS

SS

M

M

M

M

Ph2P

Ph2P PPh2

PPh2

Ph2P

PPh2Ph2P

PPh2

SS S SPh3PAu AuPPh3

2+

X2

+Reflux for 3 hours

C6H5Cl

NaBH4THF/OH- aqueous,r.t., 24 hours

H+

(H2SAnS)

2 equiv. of [Cu2(�-dppm)2(CH3CN)2](PF6)2 or [Ag2(�-dppm)2](ClO4)2 , excess NEt3, inTHF/acetone at r.t., in absence of light,overnight

2 equiv. of Ph3PAuCl,excess KOH, inMeOH/CH2Cl2/acetone

at r.t., in absence oflight, overnight

[(M2(�2-dppm)2)2(�2-�2-SAnS)]X2: M = CuI, X = PF6

-, (9); M = AgI, X = ClO4

-, (10)

(Ph3PAu)2(�-SAnS-SAnS) (11)

Scheme 4.1. Synthesis route for the ligand H2SAnS and complexes 9-11

59

(a)

(b)

Figure 4.4. ORTEP drawing of 9·3CH3CN·Et2O·0.5H2O (a) and 10·4.6CH3CN (b) (for clarity, phenyl rings are in thin line format and all H atoms, anions and non-ligating solvent molecules are omitted)

60

9�3CH3CN�Et2O�0.5H2O 10�4.6CH3CN Distance (Å)

Cu1-N1 2.060(4) Ag1-N1 2.458(7) Cu1-P1 2.2796(10) Ag1-P1 2.4962(17) Cu1-P4 2.3124(10) Ag1-P4 2.5118(17) Cu1-S1 2.4355(11) Ag1-S1 2.6283(16) Cu1���Cu2 2.7449(7) Ag1���Ag2 2.9318(8) Cu2-P2 2.2189(10) Ag2-P3 2.4378(17) Cu2-P3 2.2626(11) Ag2-P2 2.4981(18) Cu2-S1 2.2836(11) Ag2-S1 2.5899(15) S1-C4 1.783(4) S1-C1 1.787(6)

Angle (˚) N1-Cu1-P1 108.23(13) N1-Ag1-P1 102.74(19) N1-Cu1-P4 99.80(11) N1-Ag1-P4 92.90(18) P1-Cu1-P4 123.34(4) P1-Ag1-P4 127.61(5) N1-Cu1-S1 105.27(13) N1-Ag1-S1 107.57(18) P1-Cu1-S1 120.77(4) P1-Ag1-S1 106.90(5) P4-Cu1-S1 96.43(4) P4-Ag1-S1 115.37(5) N1-Cu1-Cu2 157.10(13) N1-Ag1-Ag2 160.58(19) P1-Cu1-Cu2 86.09(3) P1-Ag1-Ag2 91.90(4) P4-Cu1-Cu2 86.10(3) P4-Ag1-Ag2 88.02(4) S1-Cu1-Cu2 51.89(3) S1-Ag1-Ag2 55.20(4) P2-Cu2-P3 126.16(4) P3-Ag2-P2 128.97(6) P2-Cu2-S1 134.42(4) P3-Ag2-S1 122.56(5) P3-Cu2-S1 98.59(4) P2-Ag2-S1 103.01(6) P2-Cu2-Cu1 101.61(3) P3-Ag2-Ag1 95.43(4) P3-Cu2-Cu1 100.51(3) P2-Ag2-Ag1 91.27(4) S1-Cu2-Cu1 57.06(3) S1-Ag2-Ag1 56.44(4) C4-S1-Cu2 108.14(13) C1-S1-Ag2 127.8(2) C4-S1-Cu1 124.23(14) C1-S1-Ag1 95.20(19) Cu2-S1-Cu1 71.05(3) Ag2-S1-Ag1 68.36(4)

two metal atoms bridged by dppm at each side of the anthracenyl group are asymmetrical

due to the coordination between only one of them and a solvent molecule CH3CN. The

metal-nitrogen bond lengths are 2.060(4) Å and 2.458(7) Å, respectively in 9 and 10.

Table 4.1. Selected interatomic distances and angles of complexes 9 and 10

61

These values are in accord with those of other CuI/AgI complexes containing ligating

CH3CN such as [Cu2(�-dppm)2(CH3CN)4](ClO4)2 (Cu-N: 1.999Å and 2.160Å)79 and

[(PPh3)2Ag(CH3CN)](BF4) (Ag-N: 2.321Å).80 The Cu-S distances in 9 are 2.2836(11)Å

and 2.4355(11)Å, and similar to other reported polynuclear CuI-thiolate structures such as

[Cu2(PPh3)4(�-SPh)2](Cu-S: 2.34 and 2.42Å).73f The Ag-S distances in 10 are

2.5899(15)Å and 2.6283(16)Å which is similar to a recent example of AgI-S complexes

[Ag4(�2-dppm)4(S2CC(CN)P(O)(OEt)2)2](Ag-S: 2.56-2.65Å).74c The short metal-metal

separations of 2.7449(7)Å and 2.9318(8)Å in 9 and 10 respectively indicate the existence

of intramolecular CuI-CuI/AgI-AgI interactions. The Cu-S-Cu angle of 71.05(3)˚ in 9

compares favorably with those found in some CuI complexes which containing bridging

thiolates such as [Cu4(�2-dppm)3(�2-�2-NS2)(�2-�4-NS2)] (NS22-=1,8-

naphthalenedithiolate) (60.06(6)˚ to 80.95(7)˚).73c The Ag-S-Ag angle of 68.36(4)˚ in 10

is also close to those of other AgI thiolate complexes such as [(PPh3) Ag (S-tmhd)]2 (S-

tmhd: thiolate of 5-mercapto-2,2,6,6-tetramethyl-4-hepten-3-one) (68.17˚).74f

Actually even when the reaction was started with the same reactants ratio of Yam’s,76

the products remained not the trinuclear analogues proposed by her, but the bis-dinuclear

complexes 9 or 10 (with a relatively lower yield). This may be due a steric reason caused

by a relative large substituent of anthracenyl group on S atom. In addition, structural

studies of these complexes suggests that it may be the intramolecular edge-to-face �-�

interactions between the anthracenyl ring and some of the phenyl rings of dppm (Figure

4.5) that help stabilize such structures of relatively low nuclearity. In the structure of 9,

there are two phenyl rings from one dppm stacked aslant over each side of the

anthracenyl plane. The dihedral angle � between the planes of one of the phenyl rings

62

(C1C to C6C or C1CA to C6CA) and the corresponding benzene ring (C1, C2, C3, C5G,

C6G and C7A) of the anthracenyl moiety is 80.4º, while the centroid-centroid distance d

between them is 4.888 Å. The corresponding angles (�) and distances (d) between

another phenyl ring (C1B to C6B or C1BA to C6BA) and the ring (C5, C6, C7, C1G,

C2G and C3G) of the anthracenyl moiety with which it interacts are 69.9º and 4.675 Å,

respectively. These parameters are within the range (30º<�<90º, 4.5Å<d<7Å) for typical

edge-to-face �-� interactions.40 The corresponding � and d between those two phenyl

rings of dppm are 16.6º and 3.825 Å respectively, which suggests an off-set �-� stacking

(a) (b)

Figure 4.5. �-� stacking geometry in 9·3CH3CN·Et2O·0.5H2O (a) and 10·4.6CH3CN (b)

63

between them.38 In the structure of 10, there is only one phenyl ring of dppm (C1G to

C6G and C1GA to C6GA) interacting with the central benzene ring (C1, C2, C7, C1A,

C2A and C7A) of the anthracenyl ring over each side. The corresponding � and d are

89.3º and 4.772Å respectively.

Treatment of SAnS2- with dinuclear gold(I) starting material (�-dppm)(AuCl)2 or

[Au2(�-dppm)2](ClO4)2 gave some dark red solid, which is too insoluble in common

organic solvents to be well characterized. These compounds are therefore suspected to be

some polymers of gold thiolate complexes. However, the reaction between SAnS2- and

the mononuclear gold starting material Ph3PAuCl with a reported method48c afforded

complex 11 formulated as (Ph3PAu)2(�-SAnS-SAnS) with a low yield of 20% (Scheme

4.1). As SAnS2- is quite reductive, there may be a competition between oxidation and

coordination during the reaction. 11 may be formed by oxidation of half of sulfur atoms

of SAnS moiety by AuI as the first step and coordination of AuI to the unoxidized sulfur

atoms as the second step. Large quantity of dark brown solids in the final reaction

mixture was filtered off during extraction of 11 with CH2Cl2. These by/side-products may

be a mixture of gold metal, potassium salts and complexes of AuI with oligomers of

SAnS moiety ((PPh3Au)2(�-SAnS-(SAnS)n-SAnS), n1). Such over-oxidations of SAnS2-

may account for the low yield of complex 11. Single crystals of 11·0.5CH2Cl2 are formed

by slow diffusion of diethyl ether vapor into a CH2Cl2 solution of 11. Its molecular

structure is depicted in Figure 4.6, and some interatomic distances and angles are listed

in Table 4.2. The P-Au-S angles are 178.51(12)º and 175.44(16)º showing a typical

linear coordination geometry of AuI. The Au-S bond lengths of 2.314(3)Å and 2.279(4)Å

compares favorably with those observed in other Au I-S complexes such as

64

Distance (Å) Angle (˚) Au1-P1 2.265(3) P1-Au1-S1 178.51(12) Au1-S1 2.314(3) P2-Au2-S4 175.44(16) Au2-P2 2.250(3) C1-S1-Au1 103.1(3) Au2-S4 2.279(4) C8-S2-S3 101.8(4) S1-C1 1.768(14) C15-S3-S2 102.1(4) S2-C8 1.772(16) C22-S4-Au2 105.1(4) S2-S3 2.082(5) S3-C15 1.787(17) S4-C22 1.785(18)

Figure 4.6. ORTEP drawing of 11·0.5CH2Cl2 (for clarity, phenyl rings are in thin line format and all H atoms and solvent molecules are omitted)

Table 4.2. Selected interatomic distances and angles of complex 11

65

[(PPh3)Au(SSNH2)](Au-S: 2.311(2)Å).75e The intramolecular Au-Au distance of 9.080Å

and the shortest intermolecular Au-Au separation of 5.027Å are too long to suggest any

Au-Au interactions between gold atoms.26m The S-S bond length of 2.082(5)Å is slightly

shorter than that of 2.1089(12)Å observed in the structure of an organic analogue di-9-

anthryl disulfide (AnSSAn).81 And the centroid-centroid distance of 3.688 Å between

their corresponding overlapped benzene rings (rings of C9 to C14 and C23 to C28)

indicates similar face-to-face �-� interaction. The C-S-S�-C� torsion angle of 66.8º in 11 is

also smaller than that of 76.1º in AnSSAn. Two anthracenyl rings connected by such S-S

bond overlap partially with a smaller dihedral angle of 24.7º between the mean planes of

them than that of 37.1º in AnSSAn. These geometry parameters indicate that the two

anthracenyl rings in 11 are stacked closer with each other than those in AnSSAn. This

may be due to the fact that the � electron density of the anthracenyl ring is reduced by

electron-withdrawing from Ph3AuS- moiety and therefore the repulsion between the �

electron clouds of the two anthracenyl rings are reduced, which makes the two rings be

able to get closer to each other.

4.3.2 Electronic absorption and emission spectroscopy

The electronic absorption spectrum of SAnS2- is shown in Figure 4.7. The intense

vibronic absorption bands ranging from 370 nm to 600 nm show large red-shifts and

broadening compared to the ���* transition absorption bands of anthracenyl rings

(ranged from 350 nm to 450 nm) of PAnP and its AuI complex in our previous study.18, 19

Such red-shifts and broadening may be attributable to ���* transitions of anthracenyl

rings with mixing of n(S)��* transitions. The absorption spectra of 9, 10 and 11 also

display similar vibronic bands but with different degrees of blue-shifts compared to those

66

for SAnS2-. These blue-shifts may originate from the energy drop of n(S) orbital caused

by the electron density decrease on sulfur atoms in these complexes. Such band shifts for

AuI complex 11 is the largest due to three possible reasons. First, half of the sulfur atoms

in 11 are oxidized to -1 that dramatically reduces their electron density. Second, due to

relativistic effects35a, AuI may have much stronger electron withdrawing ability than CuI

300 400 500 600 7000

10000

20000

30000

40000

50000

60000

70000

80000

90000

100000

SAnS2-

910

11

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

Figure 4.7. UV-visible absorption spectra of SAnS2- and complexes 9-11 at room temperature (Sample solution of SAnS2- was prepared by mixing H2SAnS with excess NaBH4 in ethanol under N2 to avoid oxidization of sulfur. This solution was then transferred via cannula into a 10-cm3

round-bottomed flask equipped with a side arm 1-cm fluorescence cuvette and sealed from atmosphere by a Knote quick-release Teflon stopper; for complex 9-11, CH2Cl2 was used as solvent)

67

and AgI. This also accords with the fact that the ionization potential of atomic gold is

much higher than those of atomic copper and silver (Cu, 7.73 ev; Ag, 7.58 ev; Au, 9.23

ev).82 Third, the ancillary ligand PPh3 has weaker electron donating ability than dppm

and thus may indirectly lead to lower electron density on sulfur(-II) atoms in 11 than

those in 9 and 10. And the reason for that complex 9 has larger blue-shifts of absorption

bands than 10, compared with SAnS2-, may only be that CuI is more electron attractive

than AgI according to a slightly lower ionization potential of atomic copper than that of

atomic silver. In addition to the ���* and n(S)��* transition absorptions, the spectra of

all three complexes also display much stronger absorption in higher energy bands

(ranging from 235 nm to 350 nm) than that of the ligand SAnS2-. This could be due to the

absorption of the phosphine ligands in these complexes. The electronic emission spectra

of the ligand SAnS2- and these complexes in degassed solutions all show a broad intense

band ranging from 460 nm to 800 nm (Figure 4.8.). Their maximum emission

500 600 700 8000

100

200

300

400

500

600

700 11 9 10SAnS2-

Nor

mal

ized

em

issi

on in

tens

ity (a

. u.)

Wavelength (nm)

Figure 4.8. Emission spectra of degassed solutions of SAnS2- (in ethanol) and complexes 9-11 (in CH2Cl2) at room temperature (excited at 300 nm)

68

wavelengths are in a sequence of 11 (536 nm)<9 (565 nm)<10 (572 nm)<SAnS2- (599

nm), which accords with their absorption spectra. Thus, these emissions are tentatively

assigned to 1(��*) with mixing of 1(n�*) fluorescence as the Stokes shifts are not quite

dramatic between emission and absorption. However, the ligand(RS-)-metal charge-

transfer (LMCT) transition emissions in the spectra of complexes 9, 10 and 11 could not

be ruled out. Previous studies suggested that such emissions in solution could be located

at a range of 546 nm to 640 nm.73c, d, 74a, 75a, b, 76 Therefore, the 1(��*) and 1(n�*) emissions

may be broad and strong enough to cover them. The photophysical data of these

compounds are listed in Table 4.3.

Absorption Emission (excited at 300 nm) Compound

�max/nm (�/M-1cm-1) �max/nm

SAnS2- 244(9850), 268(7000), 282(7040), 384(1460), 462(8090), 518(9400)

599

9 461(12530), 487(14230) 565

10 508(10440) 572

11 276(58910), 431(12410), 455(13170) 536

4.4 Conclusions

Good reactivity of ligand H2SAnS towards d10 metals has been shown in our study. The

anthracene unit of the ligand plays a role in stabilizing the structures of these complexes

by forming �-� interactions. The ligand and the complexes all show intense ligand-

centered emissions (��* and n�*) in degassed solution. The wavelength of the maximum

of such emission is tunable by treatment of the ligand with different d10 metals. Whether

Table4.3. Photophysical data of SAnS2- and complexes 9-11

69

the relative low nuclearity of complexes 9 and 10 is due to a steric reason may be further

investigated by replacing dppm with a less bulky ancillary ligand like dmpm (1, 2-

bis(dimethylphosphino)methane), which can both reduce steric repulsions between

phosphine ligands and anthracenyl moiety and eliminate any stabilizing effect caused by

intramolecular �-� interactions. If not, then possibilities for 9 and 10 to serve as

precursors to further react with other metals to form some hetero-metallic compound may

be worth exploring.

4.5 Experimetal section

General Methods. All reactions were carried out using standard Schlenck techniques.

AgClO4, dppm and PPh3 purchased from Aldrich and KAuCl4.xH2O obtained from

Oxkem were used without further purification. All solvents used for syntheses and

spectroscopic measurements were purified according to the literature methods. [Cu2(�-

dppm)2(CH3CN)2](PF6)2 and [Ag2(�-dppm)2](ClO4)2 were prepared by reacting of 1

molar equiv. of dppm with [Cu(CH3CN)4]PF6 in CH2Cl2 and AgClO4 in CH3CN,

respectively. PPh3AuCl was prepared by reacting of 2 molar equiv. of PPh3 with

KAuCl4.xH2O in methanol.

CAUTION! Perchlorate salts of metal complexes with organic ligands are potentially

explosive and should be handled in small quantities with care.

9, 10-anthracenedithiol (H2SAnS): separate solutions of 1.5 g (7.2 mmol) of

anthraquinone in 60 ml of chlorobenzene and 3.0 g (7.4 mmol) of Lawesson’s reagent in

30 ml of chlorobenzene were heated till boiling. Then the hot solution of the latter was

transferred into that of the former using a dropper. The mixture was then refluxed for 3

hours to form red precipitate, which was filtered and washed three times successively

70

with hot chlorobenzene and CH2Cl2. The precipitate was then dried and re-refluxed in

100 ml of ethanol for 2 hours. Next, the precipitate was filtered and washed twice more

with ethanol to form bright red microcrystalline solid, which is regarded as anthracene

polydisulfide. 1.0 g (4.2 mmol) of this polydisulfide was added to a mixture of 50 ml of

THF and 50 ml of 10% NaOH aqueous solution and was stirred for 5 minutes. 1.0g (9.7

mmol) of NaBH4 was dissolved in 15 ml of 10% NaOH aqueous solution and was then

added dropwise into the above reaction mixture using a syringe. The reaction mixture

was then stirred overnight at room temperature, before being poured into iced 500 ml of 6

N HCl solution. The resulting yellow precipitate was recovered by filtration, washed

several times with water and then twice more with ethanol and dried in vacuum. Yield:

60%. Anal. Calc. for C14H10S2: C, 69.4; H, 4.16; S, 26.5. Found: C, 68.9; H, 4.12; S, 25.6.

1H NMR (300 MHz, CD2Cl2, /ppm): 8.74-8.69 (m, 4H, H1, 4, 5 and 8 of anthracenyl ring),

7.65-7.60 (m, 4H, H2, 3, 6 and 7 of anthracenyl ring), 3.70 (s, 2H, -SH). Negative-ESI/MS

(m/z): 241 [M-H]-.

[(Cu2(�2-dppm)2)2(�2-�2-SAnS)](PF6)2 (9): 0.036 g (0.15 mmol) of H2SAnS was stirred

with excess triethylamine in 15 ml of THF for several minutes. The above solution was

then transferred into 40 ml of acetone solution of 0.376 g (0.3 mmol) of [Cu2(�-

dppm)2(CH3CN)2](PF6)2 via cannula. After being stirred in absence of light overnight, the

reaction solution was filtered. The filtration was concentrated by rota-evaporation. Excess

of diethyl ether was added to precipitate the product as a reddish orange solid. Analytical

pure complex was obtained by recrystallization in CH2Cl2/Et2O. Yield: 80%. Anal. Calcd

for C110H96 Cu4 F12P10S2: C, 58.1; H, 4.3. Found: C, 57.7; H, 3.8. 1H NMR (300 MHz,

CD2Cl2, /ppm): 8.71-8.67 (m, 4H, H1, 4, 5 and 8 of anthracenyl), 7.28-7.14 (m, 80H, Ph),

71

6.38-6.35 (m, 4H, H2, 3, 6 and 7 of anthracenyl), 3.08 (broad, 8H, PCH2P); 31P{1H}-NMR

(121.5 MHz, CD3CN, /ppm): -7.19 (s, CH2PPh2), -142.89 (sept, PF6)

[(Ag2(�2-dppm)2)2(�2-�2-SAnS)](ClO4)2 (10): procedures are the same as those for 9,

except that [Cu2(�-dppm)2(CH3CN)2](PF6)2 was replaced by [Ag2(�-dppm)2](ClO4)2.

Yield: 75%. Anal. Calcd for C110H96Ag4Cl2O8P8S2: C, 56.0; H, 4.1. Found: C, 56.3; H,

3.7. 1H NMR(300 MHz, CD2Cl2, /ppm): 9.08-9.04 (m, 4H, H1, 4, 5 and 8 of anthracenyl),

7.40-7.00 (m, 80H, Ph), 6.58-6.55 (m, 4H, H2, 3, 6 and 7 of anthracenyl), 3.09 (broad, 8H,

PCH2P); 31P{1H}-NMR(121.5 MHz, CD2Cl2, /ppm): 4.05 (broad, and no clear Ag-P

coupling observed. This may be due to some equilibrium between dissociation and re-

association in solution.)

(Ph3PAu)2(�-SAnS-SAnS) (11): 0.073 g (0.3 mmol) of H2SAnS was stirred with excess

KOH in 30 ml of MeOH for several minutes. The above solution was then transferred via

cannula into a solution of 0.3 g (0.6mmol) of Ph3PAuCl in 30 ml of CH2Cl2 and 25 ml of

acetone. After being stirred in absence of light overnight, the reaction mixture was dried

by rota-evaporation. The residues were treated with 40 ml of CH2Cl2 to get a red

suspension, which was filtered then. The filtrate was concentrated by rota-evaporation.

Excess of diethyl ether was added to precipitate the product as a reddish orange solid.

Analytical pure complex was obtained by recrystallization in CH2Cl2/Et2O. Yield: 20%.

Anal. Calcd for C64H46Au2P2S4�CH2Cl2: C, 52.6; H, 3.3. Found: C, 53.1; H, 3.5. 1H NMR

(300 MHz, THF-d8, /ppm, numbering referring to Figure 4.9.): 9.37 (d, 4H, H1, 1�, 8 and

8�), 8.18 (d, 4H, H4, 4�, 5 and 5�), 7.46-7.40 (m, 30H, Ph), 7.05 (t, 4H, H2, 2�, 7 and 7�), 6.89 (t,

4H, H3, 3�, 6 and 6�), 31P{1H}-NMR (121.5 MHz, THF-d8, /ppm): 37.5 (s)

72

S SSS

H1

H8

H7 H6

H5

H4

H3H2

H1'

H8'

H7'H6'

H5'

H4'

H3' H2'

AuPPh3Ph3PAu

Figure 4.9. Numbering of H atoms of anthracenyl rings of complex 11

73

Part II.

Synthesis and Spectroscopic Studies of Heterobimetallic

Platinum(II)-acetylide and Platinum(0)-acetylene Complexes

74

Chapter 5

Introduction on Metal Acetylide/Acetylene Complexes of

Electrochemical and Electronic Spectrocopic Properties

75

Multinuclear metallo-organic complexes bearing C�C based linkers have received a

good deal of attention over the past two decades, because of their intriguing chemical and

physical properties.83 As the electronic communication between metal centers through the

linker can be anticipated, this kind of compounds possesses potential applications in

molecular-scale electronics and nonlinear optical materials.83 The choice of acetylenes

(especially polyacetylenes) as spacers is due to the consideration of their high electronic

delocalization through the organic chain, which is necessary for giving good

intramolecular conductivity or molecular hyperpolarizability.84 The introduction of

metal-based end-groups into the organic molecule has provide a significant advantage

over pure organic counterparts, that the end-group may be redox-active, so that a charge-

carrier can be introduced to the system by a simple change of the oxidation state of the

metal, and the degree of electronic communication between the metal termini through the

bridging ligand can be measured easily. Measuring the conductivity of a single molecular

strand requires an interface between molecular and macroscopic components, which

presents obvious technical difficulties. Consequently, as much simpler indirect methods,

standard spectroscopic methods (UV-visible spectrometry, electrochemistry) are often

used to quantify electronic coupling between remote sites (end-groups) situated along the

molecule. These methods often involve the formation of a mixed-valence (MV)

complex.85

5.1 Mixed-valence complexes

A simplest mixed-valence complex is composed of two metal ions of different oxidation

states linked by an organic bridge. An electronic interaction between the remote metal

centers occurs when the d-electrons of the metal ions are in �-symmetry orbitals which

76

can effectively overlap with the �-orbitals of the bridging ligand, and are therefore

delocalized to some extent across the conjugated bridge. As the two metal ions are in

different oxidation states, charge can transfer from one to the other via either electron

transfer or hole transfer mechanism (shown in Scheme 5.1).86 Based on the extent of

charge delocalization, Robin and Day classified MV complexes into three types: class I,

completely valence trapped (no coupling between metal ions); class II, valence trapped

(weak coupling between metal ions); class III, delocalized valence (strong coupling

between metal ions).87 The situations of classes I, II and III are illustrated by classical

potential energy-configuration diagrams shown in Scheme 5.2. For class I MV

complexes, in Scheme 5.2A, the two energy curves, representing the two states of the

MV complexes (before and after charge transfer, respectively), intersect without any

splitting of the curves. The absence of splitting means that there is no electronic coupling

(charge delocalization) in this class of MV complexes. In contrast, for class II MV

complexes (Scheme 5.2B), a small splitting of the two curves exists due to weak

Mn+ bridgeM(n+1)+ M(n+1)+ bridge

Mn+

electron

electron

Mn+ bridgeM(n+1)+ M(n+1)+ bridge

Mn+

hole

holeor

Scheme 5.1. Electron transfer or hole transfer mechanism in MV complexes

77

electronic coupling between two metal centers. The extent of splitting, HAB (electronic

coupling parameter), reflects the extent of charge delocalization. The larger HAB is, the

higher extent of charge delocalization exists. By absorbing a photon with energy of Eop,

one state can switch to the other. Such kind of photo-induced charge transfer will give

rise to an absorption band in the UV-vis or near infrared absorption spectra of class II

MV complexes, which is known as intervalence-charge-transfer (IVCT) transition. The

Eop2HAB

2HAB

Energy

Energy

Energy

Reaction coordinate

Reaction coordinate

Reaction coordinate

(A) (B)

(C)

Scheme 5.2. Potential energy-configuration diagrams for MV complexes: (A) for class I; (B) for class II; (C) for class III.

78

information of the IVCT band can be used to estimate the magnitude of HAB. For class III

MV complexes (Scheme 5.2C), due to strong electronic coupling between the metal

centers, the two curves merge and give a relatively large splitting. This means that there

is only one state (ground state) in this class of MV complexes, due to a complete charge

delocalization over the entire molecule. In other words, the charge can transfer freely

from one metal center to the other without acquiring any energy, which means no IVCT

absorption band would be observed for Class III MV complexes (though there may be an

intense low energy absorption band, usually in the near infrared region, which is due to

the electronic transition from the ground state to the excited state).

Another important parameter in the study of a MV complex is the comproportionation

constant (Kc) of the redox equilibrium (shown in Scheme 5.3) between the MV state and

two iso-valence states (fully-reduced and fully-oxidized), which is a measure of the

stability of the MV complex. Due to electronic communication between two metal

centers in the MV state, the redox potential (E1) of the oxidation of the fully-reduced state

to the MV state will be different from that (E2) of the oxidation of the MV state to the

Mn+ bridgeMn+ bridge

M(n+1)+M(n+1)+ bridgeM(n+1)+Mn+ +

Kc

fully-reduced state fully-oxidized state MV state

2

Scheme 5.3. Comproportionation equilibiurm for MV complexes

Kc = e

F___RT �E1/2

(Equation 5.1)

79

fully-oxidized state. This can also be understood in the way that: oxidation of the first

metal center results in a change of electron density that is communicated to the other

metal center across the bridging ligand; the second metal center ‘feels’ the additional

charge and for simple electrostatic reasons becomes more resistant to a change in

oxidation state than the first one was. As E1 and E2 can be easily obtained by cyclic

voltammetry or differential pulse voltammetry, the value of Kc can be calculated from

Equation 5.1 by using the difference between E1 and E2 (�E1/2 = E2-E1).

5.2 C�C based bridges in mediating electronic communication

The bridging entity plays a key role in determining the extent of electronic coupling

between the metal centers in the molecular strand.88 Acetylene/acetylide species are

regarded as one of the most important bridges for two reasons. First, high �-conjugation

of the C�C bond gives rise to the presence of �-back bonding between d� orbital of the

metal and �* orbital of the bridge, which can facilitate electron delocalization. Second,

the synthetic versatility of acetylenes (Heck coupling, oxidative Glaser coupling,

Sonogashira coupling, etc.) provide much convenience for controlling the scale (length)

of the molecule, which is an important factor affecting the conductivity of the molecule

and the extent of the electronic coupling between the metal centers. Many complexes

have been synthesized by using polyynes as bridges, which are also known as wirelike

carbon chains.89 Some examples of this type of complexes are shown in Figure 5.1. The

bridge of C20 composed of 10 C�C bonds in the Re(I) complex is one of the longest

chains between two metal atoms so far reported.89i The pure carbon chains can be

modified by introducing aromatic groups into them to give another series of bridging

ligands (shown in Figure 5.2). Such kind of modification involves either attaching

80

aromatic groups like a 2, 2�:6�, 2��-terpyridyl group to the termini of the carbon chain, or

inserting an aryl ring like an anthracenyl ring in the chain. 90 Oligopyridino groups are

usually chosen in the former strategy of modification due to their exceptional

coordinative properties. In the latter strategy, fused aryl rings are usually used as

insertions due to their potential abilities to operate as a relay for triplet energy transfer

ReON

Ph3P

Re NO

PPh3

Pt Pt

(p-tol)3P

(p-tol)3P

P(p-tol)3

P(p-tol)3

MeMe

Fe FePh2P

PPh2

Ph2P

PPh2

Figure 5.1. Examples of complexes bearing wirelike carbon chains

N

N N

N

N

N

N

N

N

N

Figure 5.2. Two examples of oligopyridino acetylene ligands as bridging units

81

between terminal metal groups, which is important in making photoactive molecular-

scale wires. Another kind of modification to the carbon chain is inserting a transition

metal moiety in it, which has received great attention in search for conducting polymers

and molecular wires. The effect of such transition metal moieties on the bridge’s ability

of mediating electronic communication between two redox-active centers depends on

both the nature of the transition metal atom and properties of the ancillary ligands

coordinated to the metal. Figure 5.3 shows several examples of this class of complexes.91,

92 While the Pt center in complexes A leads to poor electronic coupling between the two

redox-active Fe centers through the bridge, the Ru center in complexes B makes such

electronic coupling much stronger. And the ancillary ligand (L) effect on the extent of

electron delocalization has been investigated based on complexes C. And it showed that

the electronic coupling was stronger in the case where the ancillary ligands are �-

donating ligands such as P(OMe)3 and pyridine, than in the case where they are �-

accepting ligands like CO.

In search for new types of bridging units for mediating electronic communication, our

group has tried to introduce metal clusters into the carbon chain. The synthetic strategies

Fc Pt

L

Fc

L

Fc Ru Fc

PBu3L'

OCPBu3

Fc Ru Fc

PP

PP

P PFeFc:

: dppmL = PBu3, P(p-tolyl)3 or PPh2Me L' = CO, pyridine or P(OMe)3

A B C

Figure 5.3. Examples of transition metal moieties as part of a bridge

82

were attaching a redox-active ferrocenylacetylide group on either each side of a trinuclear

plane of CuI, 93 or each end of a PtI-PtI �-bond.94 The structures of these molecules are

shown in Figure 5.4. The electrochemical studies showed that: while the electronic

coupling between the two Fe centers was weak in compound I (�E1/2 = 110+14 mV, Kc =

77+30), that was much stronger in compound II (�E1/2 = 267+10 mV, Kc =

33000+15000). The electronic communication in compound II was switched off upon a

side-coordination of AuI to the PtI-PtI moiety, which was shown by the electrochemical

study of compounds III (�E1/2 < 70 mV, Kc < 15).

5.3 Photophysical properties

Besides electrochemical (or chemical) oxidation/reduction of one of the terminal groups

of the wirelike molecule, selective illumination into a preferred chromophore of the

molecule provides another way to activate the system for electron/photon transfer.

Photoactivation is highly selective, extremely versatile and rapid. Many molecules have

recently been made which absorb a photon of light at one end and, following internal

Figure 5.4. Examples of transition metal clusters for mediating electronic communication between two Fe centers

Fc Pt Pt Fc

P

P

P

P

Fc Pt Pt Fc

P

P

P

P

AuX

Fc Fc

P P

CuCu

Cu

P P

P

P

P

P

+

FeFc: : dppm

X = Cl or Br

III

III

83

energy transfer across a conjugated bridge, re-emit a photon at the other end.90, 95 Such

kind of molecules is known as photonic wires (or photoactive molecular-scale wires). A

representative species are polypyridine acetylene complexes of RuII/OsII, photophysics of

which are dominated by low-lying metal-to-ligand charge transfer (MLCT) triplet excited

states. An example is shown in Figure 5.5. 95b

Another important reason for investigation of the luminescent behaviors of the metallo-

organic complexes of acetylene/acetylide ligands is that, these systems can possess

MLCT or ligand-to-metal charge transfer (LMCT) bands in the visible region of the

spectrum, which are usually associated with large second-order nonlinear optical (NLO)

activity.96 Therefore, search for complexes of low-lying MLCT excited states has

received great attention recently. Besides the polypyridine complexes of RuII, another

extensively studied system is ReI diimine acetylide complexes.97 As good �-donor ligands,

acetylide moieties are introduced into such ReI diimine system to render the metal center

more electron rich and therefore raise the energy of d-d states, which is believed to

N

N

NN

N

N

Ru

N

N

NN

N

N

Os

h� h�'

4+

Figure 5.5. An example of photonic wires

84

improve the population of the MLCT state. For instance, the complex

[Re(tBu2bpy)(CO)3(C�CC�C)Re(tBu2bpy)(CO)3] (tBu2bpy = 4, 4�-di-tert-butyl-2, 2�-

bipyridine) shown in Figure 5.6 was observed to give low-lying emission at 750 nm

upon excitation at � 450 nm, which was assigned to a 3MLCT (d�(Re)��*(C�CC�C-

Re)) transition.97b

5.4 Objectives

As our continuous interest in looking for new types of bridging units for mediating

electronic communication, an objective of this part of work was to investigate the effect

of metal-metal interactions on electronic communication in PtII acetylide complexes. The

structure of target molecules is shown in Figure 5.7. Though the mononuclear PtII

species (complexes A in Figure 5.3) have been reported to show very poor electronic

communication behavior,91 we are interested to find out whether the disturbance of the

electronic environment around the PtII center caused by the Pt-M interaction is able to

switch on such electronic communication between two redox-active Fe centers. The

Re C

CC

C

NN

N N

O

O

O C C C Re

C

N

C

N

C O

O

O

NN

:

Figure 5.6. Structure of a low-lying 3MLCT emissive complex [Re(tBu2bpy)(CO)3(C�CC�C)Re(tBu2bpy)(CO)3]

85

presence of Pt-M interaction is guaranteed by the use of the short lengthen bidentate

bridging ligand dppm, which is a typical strategy for preparing such kind of dinuclear

complexes. The results are shown and discussed in Chapter 6.

Another objective of my work was to elucidate the electronic structures of a series of

Pt(0)-acetylene complexes in ground and excited states via electronic spectroscopic study.

The structure of these complexes is shown in Figure 5.8. Compared to PtII-acetylide �-

Pt

Ph2P

Ph2P

PPh2

M(L)

PPh2

Fc

Fc

M = Au, Ag, Cu, Hg, Rh, W, Mo or Pt;L = ancillary moiety which helps saturate coordination on M

FeFc:

Figure 5.7. Structures of target molecules for the first objective of this part of my work

R RnPt

L L

L L = (PPh3)2 or dppp

R = Ph or CH3;n = 1 or 2;

Figure 5.8. Structures of target molecules for the second objective of this part of my work

86

conjugated complexes, the electronic spectroscopic properties of which have been

extensively studied,98 Pt(0)-acetylene complexes have been sparsely reported on such

properties.99 The low oxidation state (electron richness) of the Pt atoms in the Pt(0)-

acetylene complexes can keep the d� orbitals of the metal high in energy, and therefore

improve the population of low-lying d�(Pt)��*(acetylene) MLCT excited states. This is

supported by Forniés and coworkers’ computational study of a model complex

[(Pt(PH3)2)2(HC�C-1,4-C6H4-C�CH)] (Figure 5.9).99a Their extended Hückel

calculations showed that the HOMO in the model complex had half-and-half metal-

carbon character, while the LUMO was mainly localized in the �* orbital of the acetylene.

Accordingly, they assigned the vibronic emission band at 550-670 nm in the complex

[(Pt(PPh3)2)2(HC�C-1,4-C6H4-C�CH)] to be of essential MLCT character. To our best

knowledge, this is the only reported example on observation of the MLCT luminescence

of Pt(0)-acetylene complexes, though such MLCT transitions have been noticed several

times in the UV-vis spectra of this type of complexes.99 For our study, acetylene ligands

with different length of carbon chains (C2 or C4) were chosen for comparison, through

Pt

Pt

L L

L L

L = PPh3;L = PH3 (model for calculations)

Figure 5.9. Structures of complexes [(PtL2)2(HC�C-1,4-C6H4-C�CH)]

87

which we hoped to know the situation of the electron delocalization along the conjugated

chains in the excited states of the complexes. And different terminal substituent groups

(Ph- and CH3-) of acetylene were selected to find out how the effect of them on the

luminescent behavior of the complexes is. In addition, ancillary ligands (PPh3; dppp, 1, 3-

bis(diphenylphosphino)propane) on Pt atoms of different electron donating properties

were also adopted for comparison, with expectation that they may affect the MLCT

excited states of the complexes by tuning the electronic density on the Pt atoms. Results

of this work are discussed in Chapter 7.

88

Chapter 6

Synthesis and Electrochemical Studies of Heterobimetallic

Platinum(II) Ferrocenylacetylide Complexes

89

6.1 Introduction

The use of bis(diphenylphosphino)methane (dppm) or related ligands in the construction

of bimetallic and trimetallic complexes has developed tremendously in the past two

decades.100 In particular, dppm-bridged complexes of platinum or palladium have

received considerable attention. Notably, Shaw and coworkers have systematically

developed the synthesis methods for a series of hetero-bimetallic platinum

complexes, structure frame of which is shown in Figure 6.1.101, 102 Che and coworkers

then investigated the electronic spectroscopic properties of some of this type of

complexes.103 As is mentioned in the above chapter, the objective of my work on this

type of complexes was to investigate how Pt-M interactions may affect the ability of the

C�C-Pt-C�C bridge for mediating electronic communication. The ferrocenyl group, a

redox-active center, was chosen as the terminus of the C�C-Pt-C�C backbone to serve as

an electrochemical probe.

6.2 Results and discussion

Pt

Ph2P

Ph2P

PPh2

M

PPh2

L

M = Au, Ag, Cu, Hg, Rh, W, Mo, etc.;L = -C�CR or -C�N

L

Figure 6.1 Structure frames of hetero-bimetallic platinum complexes bridged by dppm

90

Scheme 6.1 Synthesis routes for complexes 12-19: (i) benzene/THF, refluxing for 1.5 hours, followed by reacting at r. t. for 14 hours; (ii) (Ph3P)AuCl, CH2Cl2, r. t., 30 minutes, followed by anion exchanging with LiClO4 in MeOH; (iii) AgNO3, acetone, 40°C, 10 minutes; (iv) [Cu(CH3CN)4]PF6, CH2Cl2, r. t., 30 minutes; (v) HgCl2, CH2Cl2, r. t., 1 hour; (vi) trans-(Ph3P)2Rh(CO)Cl, CH2Cl2, r. t., 30 minutes, followed by anion exchanging with NH4PF6 in MeOH; (vii) fac-W(CO)3(CH3CN)3, benzene, refluxing for 2 hours; (viii) fac-Mo(CO)3(CH3CN)3, benzene, refluxing for 2 hours.

6.2.1 Synthesis and characterization

The synthesis routes and nomenclatures of complexes 12-19 are illustrated in Scheme

6.1. All of complexes 12-19 except 15 were synthesized according to Shaw’s methods101

Fc Pt Fc

Ph2P

PPh2

PPh2

Ph2P

1 Pt(�-dppm)Cl2 + 1 dppm + 2 FcC�CLi

Pt

Ph2P

Ph2P

PPh2

Au

PPh2

Fc

Fc

ClO4-

Pt

Ph2P

Ph2P

PPh2

Hg

PPh2

Fc

Fc

Pt

Ph2P

Ph2P

PPh2

Ag

PPh2

Fc

Fc

Pt

Ph2P

Ph2P

PPh2

W(CO)3

PPh2

Fc

Fc

Pt

Ph2P

Ph2P

PPh2

Mo(CO)3

PPh2

Fc

Fc

Pt

Ph2P

Ph2P

PPh2

Cu

PPh2

Fc

Fc

Pt

Ph2P

Ph2P

PPh2

Rh(CO)

PPh2

Fc

Fc

Cl

Cl

O

N

O

O

+

PF6-

+

PF6-

+

trans-Pt(C�CFc)2(�1-dppm)2 (12)

[Pt(C�CFc)2(�-dppm)2Au](ClO4) (13)

[Pt(C�CFc)2(�-dppm)2Ag](NO3) (14)

[(FcC�C)Pt(�-dppm)2(�, �2-C�CFc)Cu](PF6) (15) Pt(C�CFc)2(�-dppm)2HgCl2 (16) [(FcC�C)Pt(�-dppm)2(�, �2-C�CFc)Rh(CO)](PF6) (17)

(FcC�C)Pt(�-dppm)2(�-C�CFc)W(CO)3 (18)

i

ii

iii

iv

vvi

vii

viii

FeFc:

(FcC�C)Pt(�-dppm)2(�-C�CFc)Mo(CO)3 (19)

91

Figure 6.2 Formula structure of complex 20

for preparing analogous acetylide complexes. The Pt-Cu complex (15) was prepared by

reaction between complex trans-Pt(C�CFc)2(�1-dppm)2 (12) and one molar equivalent

[Cu(CH3CN)4](PF6). The formula structure the mononuclear complex trans-

Pt(C�CFc)2(PPh2Me)2 (20) is shown in Figure 6.2. Complex 20 was prepared by the CuI

catalyzed reaction of cis-Pt(PPh2Me)2Cl2 with FcC�CH in the presence of diethylamine,

which is a general applicable method reported by Russo and Furlani104 for preparing such

kind of Pt acetylide complexes. Satisfactory elemental analysis results were obtained for

all of these complexes. The crystal structures of all of them except complex 13 (Pt-Au)

were successfully solved, which are discussed in the next section.

While complexes 13-17 and 20 are quite stable both in solid state and in solution,

complexes of trans-Pt(C�CFc)2(�1-dppm)2 (12), Pt-W (18) and Pt-Mo (19) are likely to

dissociate slightly in solution as indicated by 31P{1H}-NMR spectra (see Appendices).

The resonance signals of the decomposition species in the 31P{1H}-NMR spectrum of

complex 12 recorded in CDCl3 are at -22.17, 1.47 and 7.44 ppm. The former two are

probably due to free ligand dppm and the dinuclear platinum complex Pt2(C�CFc)4(�-

dppm)2, respectively. A proposed dissociation equation is shown in Equation 6.1.

The latter one at 7.44 ppm is due to some unknown species. Though the dissociation

FeFc:

Pt

PPh2Me

PPh2Me

Fc

Fc

trans-Pt(C�CFc)2(PPh2Me)2 (20)

92

mechanisms for complexes 18 and 19 are not clear, such dissociation may account for the

low yields of preparing these two complexes (30% and 15%, respectively). Similar

instability and difficulty in purification of this type of Pt-W and Pt-Mo hetero-bimetallic

complexes were described in Shaw’s report.101i The 31P{1H}-NMR spectra of complexes

12-19 show a typical pattern of AA�BB� system, which are in line with Shaw’s study.101

The 1H-NMR spectra of complexes of Pt-Au (13), Pt-Ag (14) and Pt-Hg (16) show only

one set of well solved peaks for methylene and ferrocenyl groups, indicating that in

solution the two ferrocenyl groups are symmetric over each side of the hetero-bimetallic

8-membered ring of PtP4C2M� (M� = Au, Ag or Hg) and so are the two H atoms of

methylene group of dppm. In contrast, the 1H-NMR spectra of Pt-Cu (15) and Pt-Rh (17)

complexes are different from those of the above complexes. The 1H-NMR spectrum of

complex 15 at room temperature (Figure 6.3) shows broad resonance peaks for

methylene and ferrocenyl groups, indicating that complex 15 is fluxional in solution. The

structure of 15 (illustrated at the top of Figure 6.3) shows that the two FcC�C- groups

play different roles in coordinating to metals: one �-bonded only to Pt and the other one

bridging Pt and Cu by being �-bonded to Pt and �-bonded to Cu (see the next section for

details of the crystal structure). Therefore, such fluxionality of 15 is ascribed to the

Pt

Ph2P

Ph2P

PPh2

Pt

PPh2

Fc

Fc Fc

Fc

Pt

PPh2

Ph2P

Fc

Fc

12

PPh2

Ph2P

2 +Ph2P PPh2

2

Equation 6.1

93

(ppm)2.42.83.23.64.04.44.85.25.66.06.46.87.27.68.08.4

phenyl

CHCl

H H H

H

H

H'

H'

H'

e a

0 0

2, 5 2, 5

3, 43, 4

3

(ppm)3.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.2

(ppm)3.63.73.83.94.04.14.24.34.4

H H

HH'

H

H'

H

H'

phenyl

CHCl3

ea

2, 52, 5

3, 4

3, 4

0

0

Figure 6.3 Room temperature 1H-NMR spectra of complexes 15 (upper) and 17 (bottom) in CDCl3 (their structures are shown at the top).

PtH'3

H'4H'5

H'2H2H3

H4H5

H'0

H'0H'0

H'0H0H0

H0H0

H0 H'0

Fe Fe

PPh2

PPh2

Ph2P

M

He

Ha

He

Ha

M = Cu or Rh

Ph2P

94

exchange of coordination roles between the two FcC�C- groups in solution at room

temperature. The two FcC�C- groups play similar roles in the crystal structure of

complex 17 (Pt-Rh). However, similar fluxionality is not observed in the 1H-NMR

spectrum of 17 (Figure 6.3). Instead, it shows two sets of signals for two ferrocenyl

groups, indicating that the �-bonding between the acetylide and Rh is quite stable in

solution. The one with corresponding larger values of chemical shift are assigned to the

acetylide which is �-bonded to Rh, as there may be stronger deshielding effect due to

electron withdrawing by Rh. The resonances of the two protons Ha (the axial proton, the

P-Pt-P direction is chosen as the axis) and He (the equatorial proton) of the methylene

group are also differentiated in the spectrum. According to the similar observation in the

low temperature 1H-NMR spectrum of Shaw’s analogous Pt-Rh complex,101h the septet

with a larger chemical shift (4.39 ppm) is assigned to Ha, while the unresolved broad one

with smaller chemical shift (4.09 ppm) is ascribed to He. The 1H- and 31P{1H}-NMR

parameters of complex trans-Pt(C�CFc)2(PPh2Me)2 (20) are in accordance with literature

values.91 While the ESI-MS spectra of mononuclear species of 12 and 20 and the hetero-

bimetallic complex 18 (Pt-W) display a distinct molecular ion peak of M+, those of

complexes 13-17 display a peak of [M-X]+ formed by loss of an anion X (X = ClO4-, 13;

NO3-, 14; PF6

-, 15; Cl-, 16; PF6-, 17) from the molecule. However, no assignable peaks

are observed in the ESI-MS spectrum of the Pt-Mo complex (19), indicating that complex

19 is the most unstable one among all these complexes. The IR spectra of all of

complexes 12-20 display weak and broad signals at 2026-2118 cm-1, due to typical

symmetric stretching of C�C. Though the two C�C are in different coordination modes

(nonbridging and bridging) in complexes of Pt-Cu (15), Pt-Rh (17), Pt-W (18) and Pt-Mo

95

(19), only the IR spectrum of 15 shows two resolved peaks of (C�C) at 2118 cm-1

(nonbridging) and 2074 cm-1 (bridging), respectively. In the spectra of complexes 17, 18

and 19, there is only one (C�C) observed at 2026 cm-1, 2118 cm-1 and 2107 cm-1,

respectively, assigned to the nonbridging C�C. The lack of signal for the bridging C�C in

them may due to two reasons. First, (C�C) is weak and broad in nature, which means

the two signals for bridging and nonbridging C�C may not be resolved. More possibly,

the signal for the bridging C�C may be obscured by the broad and much more intense

bands due to (C�O), which are located at 1953-1967 cm-1 in complexes 17-19.

6.2.2 Crystal structures

There are two sets of molecules (12a and 12b) with very similar structures in the crystal

lattice of the mononuclear complex trans-Pt(C�CFc)2(�1-dppm)2 (12). The molecular

structure of 12a is shown in Figure 6.4, which confirms the trans- configuration of this

complex. The metal shows a typical square planar coordination geometry, P-Pt-C angles

Figure 6.4 ORTEP diagram (thermal ellipsoid = 50%) of molecule 12a (for clarity, all phenyl rings and H atoms are omitted)

96

being 86.69(11)° and 93.31(11)°. The backbone of -C�C-Pt-C�C- linkage is nearly linear,

C-C-Pt and C-Pt-C angles being 176.9(3)° and 180.000(1)° respectively. The C�C and

Pt-C bond lengths of 1.201(5) and 1.999(4) Å are normal for Pt acetylide complexes. The

crystal structure of complex trans-Pt(C�CFc)2(PPh2Me)2 (20) (Figure 6.5) shows very

similar trans- coordination geometry of Pt to that of complex 12. The selected bond

lengths and angles in 12a and 20 are listed in Table 6.1.

The molecular structures of complexes 14-17 are shown in Figure 6.6-6.9, respectively.

In 14-17, the linearity of the -C�C-Pt-C�C- linkages are slightly reduced than that in 12,

with C-C-Pt and C-Pt-C angles ranging from 165.6(4)°-177.3(14)° and 165.19(17)°-

172.2(5)°, respectively. The heterobimetallic 8-membered rings of PtP4C2M� are in

Figure 6.5 ORTEP diagram (thermal ellipsoid = 50%) of 20 (for clarity, all H atoms are omitted)

97

12 20

Distances (Å)

Pt1-C1 1.999(4) Pt1-C1 1.9964(19)

Pt1-C1A 1.999(4) Pt1-C1C 1.9964(19)

Pt1-P1 2.2968(10) Pt1-P1 2.2925(5)

Pt1-P1A 2.2969(10) Pt1-P1C 2.2925(5)

C1-C2 1.201(5) C1-C2 1.205(3)

C1A-C2A 1.201(5) C1C-C2C 1.205(3)

Angles (°)

C1-Pt1-C1A 180.000(1) C1-Pt1-C1C 180.00(10)

C1-Pt1-P1 93.31(11) C1-Pt1-P1 87.09(5)

C1A-Pt1-P1 86.69(11) C1C-Pt1-P1 92.91(5)

C1-Pt1-P1A 86.69(11) C1-Pt1-P1C 92.91(5)

C1A-Pt1-P1A 93.31(11) C1C-Pt1-P1C 87.09(5)

P1-Pt1-P1A 180.00(4) P1-Pt1-P1C 180.00(10)

C2-C1-Pt1 176.9(3) C2-C1-Pt1 177.87(17)

C2A-C1A-Pt1 176.9(3) C2C-C1C-Pt1 177.87(17)

Table 6.1 Selected interatomic distances and angles in 12a and 20

Figure 6.6 ORTEP diagram (thermal ellipsoid = 50%) of 14�0.5Et2O (for clarity, all phenyl rings, H atoms and solvent molecules are omitted)

98

similar boat conformation. The metal-metal distances of 3.0276(3) Š(Pt���Ag), 2.8016(7)

Š(Pt���Cu), 3.1271(7) Š(Pt���Hg) and 3.0750(10) Š(Pt���Rh) in complexes 14-17,

respectively, are shorter than the sums of the corresponding van der Waals radii (3.44 Å

for “Pt + Ag”; 3.12 Å for “Pt + Cu”; 3.27 Å for “Pt + Hg”;53 > 3.07 Å for “Pt + Rh”105),

indicating the presence of weak intramolecular metal-metal interactions. And such

Pt���Ag and Pt���Rh distances in 14 and 17 are shorter than those observed in the

corresponding analogues [(PhC�C)2Pt(�-dppm)2AgI] (Pt���Ag: 3.146(3) Å) and

[(MeC�C)Pt(�-dppm)2(�,�-C�CMe)Rh(CO)](PF6) (Pt���Rh: 3.099(2) Å), respectively. In

15 and 17, one of the FcC�C- groups is �-bonded in an unsymmetric side-on fashion to

Cu and Rh atoms, respectively (Cu1-C3, 2.166(5) Å; Cu1-C4, 2.637(5) Å; Rh1-C13,

2.146(13) Å; Rh1-C14, 2.402(19) Å). Such substantially unsymmetric coordination

geometry is also shown by the large difference between the two M����Pt-C angles:

Cu1���Pt1-C1 of 137.71(14)° and Cu1���Pt1-C3 of 50.20(13)°; Rh1���Pt1-C1 of

Figure 6.7 ORTEP diagram (thermal ellipsoid = 50%) of 15�1.5CH2Cl2 (for clarity, all phenyl rings, H atoms, anions and solvent molecules are omitted)

99

143.7(4)°and Rh1���Pt1-C13 of 44.0(4)°. Such parameters in complex 17 compare

favorably with those observed in its analogue [(MeC�C)Pt(�-dppm)2(�,�2-

C�CMe)Rh(CO)](PF6) (Rh-C: 2.22(2) and 2.40(2) Å; Rh���Pt-C: 141.4(6)° and

45.8(5)°).101h In contrast, no such kind of �-bonding is observed in complexes 14 and 16,

though the square planes of the ligands at Pt atoms are also tilted such that one of the two

FcC�C- groups is moved towards the other metal center (Ag1���Pt1-C1 = 117.98(13)°;

Ag1���Pt1-C13 = 76.21(12)°; Hg1���Pt1-C1 = 78.1(4)°; Hg1���Pt1-C13 = 111.6(4)°). The

NO3- anion in complex 14 is observed to coordinate to the Ag atom through one of the

oxygen atoms with Ag-O bond length of 2.450(3) Å and Ag-O-N angle of 109.0(3)°,

whereas counteranions of PF6- in 15 and 17 are uncoordinated. The Hg atom in complex

16 adopts distorted tetrahedral coordination geometry. Atoms of P3, P4, Cl2 and Hg1 lie

in an approximate trigonal plane (the distance from Hg1 to the plane of P3, P4 and Cl2 is

0.114 Å) with the axial chloride, Cl1, oriented in a perpendicular direction (Cl1-Hg1-Cl2,

Figure 6.8 ORTEP diagram (thermal ellipsoid = 50%) of 16�1.5CH2Cl2 (for clarity, all phenyl rings, H atoms and solvent molecules are omitted)

100

90.24(12)°; Cl1-Hg1-P3, 89.96(12)°; Cl1-Hg1-P4, 97.22(11)°), resulting in a trigonal-

pyramidal arrangement. This arrangement is very similar to that of another Pt-Hg

bimetallic complex trans-[PtCl(Me)(�-dppm)2HgCl2] reported by Anderson and

coworkers.106 While the Pt���Hg distance of 3.1271(7) Šin 16 is much shorter than that of

3.302(1) Å in that analogue, the Hg1-Cl2 and Hg1-Cl1 (axial) bond lengths of 2.509(4)

and 2.716(3) Å, respectively, are quite comparable with those of 2.531(5) and 2.715(3) Å

in that analogue. According to their study, such Hg-Cl (axial) bond lengths are larger than

the values typical of four-coordinate Hg species (2.28-2.68 Å). And such elongation of

Hg-Cl bond was suggested to be related to the hybridization at Hg, C-H���Cl hydrogen

bonding and Pt���Hg bond formation. As no similar hydrogen bonding is observed in

complex 16, we attribute the elongation of Hg-Cl bond in 16 to the first and third reasons.

The C�C bond lengths in 14-17 range from 1.150(18)-1.209(6) Å, lying within the

typical range of values typical of metal acetylides (1.12-1.25 Å).107 The length difference

between the �-bonded and non-�-bonded C�C bonds in 14 and 17 (1.192(7) and 1.194(7)

Figure 6.9 ORTEP diagram (thermal ellipsoid = 50%) of 17�0.75CH2Cl2 (for clarity, all phenyl rings, H atoms, anions and solvent molecules are omitted)

101

14·0.5Et2O 15·1.5CH2Cl2

Distances (Å)

Pt1-C1 1.990(4) Cu1-C3 2.166(5)

Pt1-C13 1.997(4) Cu1-C4 2.637(5)

Pt1-P4 2.2947(10) Cu1-P3 2.2048(14)

Pt1-P1 2.2956(11) Cu1-P4 2.2094(14)

Pt1���Ag1 3.0276(3) Cu1���Pt1 2.8016(7)

Ag1-O1 2.450(3) Pt1-C1 1.993(5)

Ag1-P3 2.4674(11) Pt1-C3 2.035(5)

Ag(1)-P2 2.4852(11) Pt1-P2 2.3015(13)

N1-O3 1.231(5) Pt1-P1 2.3181(12)

N1-O2 1.236(5) C1-C2 1.194(7)

N1-O1 1.249(5) C3-C4 1.192(7)

C1-C2 1.200(6)

C13-C14 1.209(6)

Angles (°)

C1-Pt1-C13 165.19(17) C3-Cu1-P3 101.76(12)

C1-Pt1-P4 94.13(12) C3-Cu1-P4 98.21(13)

C13-Pt1-P4 90.29(12) P3-Cu1-P4 159.29(6)

C1-Pt1-P1 88.02(12) C3-Cu1���Pt1 46.21(12)

C13-Pt1-P1 88.66(12) P3-Cu1���Pt1 95.33(4)

P4-Pt1-P1 175.29(4) P4-Cu1���Pt1 102.48(4)

C1-Pt1���Ag1 117.98(13) C1-Pt1-C3 171.62(19)

C13-Pt1���Ag1 76.21(12) C1-Pt1-P2 89.08(14)

P4-Pt1���Ag1 88.58(3) C3-Pt1-P2 87.88(13)

P1-Pt1���Ag1 86.71(3) C1-Pt1-P1 90.37(14)

O1-Ag1-P3 107.61(9) C3-Pt1-P1 93.84(13)

O1-Ag1-P2 110.35(9) P2-Pt1-P1 171.04(4)

P3-Ag1-P2 141.93(4) C1-Pt1���Cu1 137.71(14)

O1-Ag1���Pt1 93.09(8) C3-Pt1���Cu1 50.20(13)

P3-Ag1���Pt1 88.53(2) P2-Pt1���Cu1 91.15(3)

P2-Ag1���Pt1 92.17(2) P1-Pt1���Cu1 83.26(3)

O3-N1-O2 121.5(4) C2-C1-Pt1 173.9(5)

O3-N1-O1 119.8(4) C4-C3-Pt1 176.4(4)

O2-N1-O1 118.7(4) C4-C3-Cu1 99.4(4)

N1-O1-Ag1 109.0(3) C4-C3-Cu1 26.48(16)

C2-C1-Pt1 165.6(4) C3-C4-Cu1 54.13(29)

C14-C13-Pt1 169.5(4)

Table 6.2 Selected interatomic distances and angles in complexes 14 and 15

102

16·1.5CH2Cl2 17·0.75CH2Cl2

Distances (Å)

Pt1-C13 2.007(13) Pt1-C1 1.978(11) Pt1-C1 2.018(14) Pt1-C13 2.020(12) Pt1-P1 2.282(3) Pt1-P2 2.276(3) Pt1-P2 2.291(3) Pt1-P3 2.313(3) Pt1���Hg1 3.1271(7) Pt1���Rh1 3.0750(10) Hg1-P4 2.492(3) Rh1-C25 1.867(18) Hg1-Cl2 2.509(4) Rh1-C13 2.146(13) Hg1-P3 2.522(4) Rh1-P4 2.310(3) Hg1-Cl1 2.716(3) Rh1-P1 2.320(3) C1-C2 1.184(18) Rh1-C14 2.402(19) C13-C14 1.150(18) C1-C2 1.194(17) C13-C14 1.183(18) C25-O25 1.182(19)

Angles (°)

C13-Pt1-C1 170.1(5) C1-Pt1-C13 172.2(5) P4-Rh1-P1 178.89(13)

C13-Pt1-P1 92.8(3) C1-Pt1-P2 87.2(3) C25-Rh1-C14 145.8(7)

C1-Pt1-P1 85.1(4) C13-Pt1-P2 93.1(3) C13-Rh1-C14 29.5(5)

C13-Pt1-P2 91.9(3) C1-Pt1-P3 92.7(3) P4-Rh1-C14 94.0(4)

C1-Pt1-P2 90.1(4) C13-Pt1-P3 87.4(3) P1-Rh1-C14 85.3(3)

P1-Pt1-P2 175.20(12) P2-Pt1-P3 177.73(12) C25-Rh1���Pt1 143.8(6)

C13-Pt1���Hg1 111.6(4) C1-Pt1���Rh1 143.7(4) C13-Rh1���Pt1 40.9(3)

C1-Pt1���Hg1 78.1(4) C13-Pt1���Rh1 44.0(4) P4-Rh1���Pt1 86.81(8)

P1-Pt1���Hg1 91.47(9) P2-Pt1���Rh1 86.23(8) P1-Rh1���Pt1 92.13(9)

P2-Pt1���Hg1 88.00(9) P3-Pt1���Rh1 92.58(7) C14-Rh1���Pt1 70.3(4)

P4-Hg1-Cl2 108.91(12) C25-Rh1-C13 175.3(7) C2-C1-Pt1 177.2(11)

P4-Hg1-P3 134.87(11) C25-Rh1-P4 90.4(4) C14-C13-Pt1 177.3(14)

Cl2-Hg1-P3 115.58(12) C13-Rh1-P4 90.8(3) C14-C13-Rh1 87.4(12)

P4-Hg1-Cl1 97.22(11) C25-Rh1-P1 90.7(4) Pt1-C13-Rh1 95.1(6)

Cl2-Hg1-Cl1 90.24(12) C13-Rh1-P1 88.2(3) C13-C14-Rh1 63.2(10)

P3-Hg1-Cl1 89.96(12) P4-Hg1���Pt1 86.43(8) Cl2-Hg1���Pt1 91.65(9) P3-Hg1���Pt1 85.17(8) Cl1-Hg1���Pt1 175.12(9) C2-C1-Pt1 172.2(14) C14-C13-Pt1 171.0(14)

Table 6.3 Selected interatomic distances and angles in complexes 16 and 17

103

Å, respectively, in 14; 1.183(18) and 1.194(17) Å, respectively, in 17) is not significant,

indicating that the �-bond between C�C and Cu/Rh may be weak. However, the �-bond

between C�C and Rh may be stronger than that between C�C and Cu, as the two

corresponding Rh-C distances of 2.146(13) and 2.402(19) Å are shorter than the Cu-C

distances of 2.166(5) and 2.637(5) Å, respectively. And this is also supported by the 1H-

NMR result that such �-bond is fluxional in complex 15, but not in complex 17. The

selected bond lengths and angles in complexes 14-17 are listed in Table 6.2 and Table

6.3.

Complexes 18 (Pt-W) and 19 (Pt-Mo) are isostructural. Their molecular structures are

shown in Figure 6.10 and Figure 6.11, respectively. The geometry of -C�C-Pt-C�C-

linkage drastically deviates from linearity with C-C-Pt and C-Pt-C angles ranging from

148.9(3)°-177.4(5)° and 168.5(2)°-168.60(15)°, respectively. This is caused by the

formation of a �-�-bonding between one of the two FcC�C- groups and two metal centers.

Figure 6.10 ORTEP diagram (thermal ellipsoid = 50%) of 18�toluene�n-hexane (for clarity, all phenyl rings, H atoms and solvent molecules are omitted)

104

In complex 18, Pt and W are asymmetrically bridged by the FcC�C- group with Pt1-C13

and W1-C13 bond lengths of 2.052(4) and 2.470(4) Å, respectively (C14-C13-Pt1 =

148.9(3)°; C14-C13-W1 = 126.3(3)°). Such W-C bond length is longer than the

corresponding one observed in the analogous complex [(p-MeC6H4C�C)Pt(�-dppm)2(�-

C�CC6H4Me-p)W(CO)3] (2.398(9) Å),101i which is longer than that (2.1-2.3 Å) found for

W-C(alkyl) �-bonds, indicating that the W-C interaction is weaker. However, such

interaction is strong enough to weaken the C�C bond, which is indicated by the fact that

the bridging C�C bond (1.213(8) Å) is slightly longer than the non-bridging one (1.188(8)

Å). The coordination geometry at W in 18 is meridonal-octahedral. The 8-membered ring

of PtP4C2W is also in boat conformation like those of complexes 14-17. The Pt���W

distance of 3.0653(2) Å in 18 is longer than that of 3.037(1) Å in the analogous complex

[(p-MeC6H4C�C)Pt(�-dppm)2(�-C�CC6H4Me-p)W(CO)3],101i indicating the presence of

Figure 6.11 ORTEP diagram (thermal ellipsoid = 50%) of 19�1.9THF (for clarity, all phenyl rings, H atoms and solvent molecules are omitted)

105

18·toluene·n-hexane 19·1.9THF

Distances (Å)

Pt1-C1 1.997(4) Pt1-C1 1.993(6) Pt1-C13 2.052(4) Pt1-C13 2.011(6) Pt1-P4 2.2966(9) Pt1-P1 2.2949(14) Pt1-P1 2.3102(10) Pt1-P3 2.3021(15) Pt1���W1 3.0653(2) Pt1���Mo1 3.1009(5) W1-C26 1.925(4) Mo1-C26 1.899(6) W1-C25 2.014(4) Mo1-C25 2.013(7) W1-C27 2.029(5) Mo1-C27 2.048(7) W1-P2 2.4355(10) Mo1-P4 2.4427(16) W1-P3 2.4422(10) Mo1-P2 2.4456(16) W1-C13 2.470(4) Mo1-C13 2.533(6) C1-C2 1.198(6) C1-C2 1.188(8) C13-C14 1.216(5) C13-C14 1.213(8) C25-O25 1.162(5) C25-O25 1.155(8) C26-O26 1.173(5) C26-O26 1.191(7) C27-O27 1.153(5) C27-O27 1.129(8)

Angles (°)

C1-Pt1-C13 168.60(15) C27-W1-P3 86.57(12) C1-Pt1-C13 168.5(2) C27-Mo1-P2 87.02(18)

C1-Pt1-P4 89.47(11) P2-W1-P3 169.58(3) C1-Pt1-P1 90.52(17) P4-Mo1-P2 169.65(5)

C13-Pt1-P4 88.28(11) C26-W1-C13 168.16(16) C13-Pt1-P1 87.32(17) C26-Mo1-C13 170.4(2)

C1-Pt1-P1 91.02(11) C25-W1-C13 107.36(15) C1-Pt1-P3 91.44(17) C25-Mo1-C13 105.2(2)

C13-Pt1-P1 89.90(11) C27-W1-C13 83.63(15) C13-Pt1-P3 89.52(17) C27-Mo1-C13 85.4(2)

P4-Pt1-P1 173.12(3) P2-W1-C13 83.88(9) P1-Pt1-P3 173.40(5) P4-Mo1-C13 84.18(13)

C1-Pt1���W1 137.95(11) P3-W1-C13 86.53(9) C1-Pt1���Mo1 136.97(16) P2-Mo1-C13 86.30(13)

C13-Pt1���W1 53.37(11) C26-W1���Pt1 149.80(13) C13-Pt1���Mo1 54.49(16) C26-Mo1���Pt1 149.13(19)

P4-Pt1���W1 93.21(2) C25-W1���Pt1 65.57(11) P1-Pt1���Mo1 92.57(4) C25-Mo1���Pt1 64.98(17)

P1-Pt1���W1 91.01(3) C27-W1���Pt1 125.34(12) P3-Pt1���Mo1 90.30(4) C27-Mo1���Pt1 125.60(19)

C26-W1-C25 84.26(17) P2-W1���Pt1 88.43(2) C26-Mo1-C25 84.2(3) P4-Mo1���Pt1 88.31(4)

C26-W1-C27 84.86(18) P3-W1���Pt1 87.13(2) C26-Mo1-C27 85.3(3) P2-Mo1���Pt1 87.04(4)

C25-W1-C27 168.79(17) C13-W1���Pt1 41.80(9) C25-Mo1-C27 169.1(3) C13-Mo1���Pt1 40.26(13)

C26-W1-P2 93.04(12) C2-C1-Pt1 176.5(4) C26-Mo1-P4 93.37(19) C2-C1-Pt1 177.4(5)

C25-W1-P2 94.96(12) C14-C13-Pt1 148.9(3) C25-Mo1-P4 95.00(18) C14-C13-Pt1 156.8(5)

C27-W1-P2 88.31(12) C14-C13-W1 126.3(3) C27-Mo1-P4 88.18(18) C14-C13-Mo1 118.0(4)

C26-W1-P3 95.54(12) Pt1-C13-W1 84.83(13) C26-Mo1-P2 95.37(19) Pt1-C13-Mo1 85.2(2)

C25-W1-P3 91.79(12) C25-Mo1-P2 91.40(18)

Table 6.4 Selected interatomic distances and angles in complexes 18 and 19

106

a weaker metal-metal interaction. The structure of complex 19 is very similar to that of

18, with Pt���Mo distance of 3.1009(5) Å. The selected bond lengths and angles in

complexes 18 and 19 are listed in Table 6.4.

6.2.3 Electronic absorption spectroscopy

The UV-visible absorption spectra of complexes 13-17 and 20 are shown in Figure 6.12

(due to their instability in solution, the electronic absorption properties of complexes

trans-Pt(C�CFc)2(�1-dppm)2 (12), 18 (Pt-W) and 19 (Pt-Mo) were not investigated). And

the absorption data (�max and �max) are summarized in Table 6.5. All spectra of the

300 400 500 600 7000

10000

20000

30000

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

13 (Pt-Au) 14 (Pt-Ag) 15 (Pt-Cu) 16 (Pt-Hg) 17 (Pt-Rh) 20

Figure 6.12 UV-vis absorption spectra of complexes 13-17 and 20 in CH2Cl2 at room temperature

107

complex �max/nm (�/M-1cm-1) 13 (Pt-Au) 333 (23710), 461 (5780) 14 (Pt-Ag) 319 (16300), 359 (sh, 7310), 430 (4200) 15 (Pt-Cu) 276 (sh, 24880), 345 (13470), 454 (4680) 16 (Pt-Hg) 406 (6450) 17 (Pt-Rh) 395 (13830), 501 (9840) 20 263 (sh, 21010), 332 (10490), 363 (8310), 445 (900)

investigated complexes display a similar broad and strong absorption band between 235

and 300 nm, which is due to the absorption from the phenyl rings in these complexes,

whereas in the region of longer wavelengths (> 300 nm) they show different absorption

bands. The mononuclear complex trans-Pt(C�CFc)2(PPh2Me)2 (20) exhibits intense

absorption bands at 332 and 363 nm (�max � 104 M-1cm-1), which is different from the

observation for similar complexes of this type. For example, the absorption spectra of

trans-Pt(C�CPh)2(PEt3)2108

and trans-Pt(C�CPh)2(�1-dppm)2103c

show only one band in

the similar region with similar intensity (�max = 328 and 345 nm, respectively), which was

assigned to the mixing of intraligand (���* of C�CPh) transition and metal-to-ligand

charge transfer (MLCT) transition (Pt(5d)��* of C�CPh). The two bands at 332 and 363

nm in the absorption spectrum of complex 20 are ascribed to the splitting of such a

mixing. In other words, they are assigned to the intraligand (���* of C�CFc) and

MLCT (Pt(5d)��* of C�CFc) transition, respectively. In addition, the absorption

spectrum of complex 20 displays a weak broad band at 445 nm (�max = 900 M-1cm-1),

which is attributed to the ligand field transition of the Fc group. This assignment is based

on the similar absorption band observed for the AgI and CuI complexes bearing FcC�C

groups.93 The absorption spectrum of complex [Pt(C�CFc)2(µ-dppm)2Au](ClO4) (13)

Table 6.5 Electronic absorption data of complexes 13-17 and 20 (solvent: CH2Cl2; at room temperature)

108

shows an intense unsymmetric absorption band at 333 nm (�max = 23710 M-1cm-1) and a

moderate intense absorption band at 461 nm (�max = 5780 M-1cm-1), which is similar to

the absorption spectrum of the analogous complex [Pt(C�CPh)2(µ-dppm)2Au](PF6) (�max

= 329 and 387 nm, respectively).103c Accordingly, the former one at 333 nm is assigned

to the mixed metal-to-alkynyl MLCT/intraligand (���* of C�CFc) transition. The latter

one at 461 nm, which is red-shifted from that of the mononuclear species 20 at 363 nm, is

attributed to the metal centered 1(d�*�p�) transition with substantial mixing of MMLCT

(metal-metal bond-to-ligand charge transfer) 1[d�*�p�/�*(C�CFc)] character, where the

d�* and p� denote the antibonding combination of dZ2(Pt)-dZ2(Au) interaction and bonding

combination of pz(Pt)-pz(Au) interaction, respectively (taking the Pt���Au direction as the

z-axis). Similar assignments have been suggested for other dinuclear d8-d8 and d8-d10

species.103a, c, 109, 110 The absorption spectra of other heterobimetallic complexes 14-17

show a similar absorption band of the mixed MLCT/intraligand transition with �max in a

range of 319-395 nm (only for the complex Pt-Hg (16), this band is not resolved,

probably obscured by the broad and intense absorption of the phenyl rings). In addition,

these spectra display the mixed metal-centered/MMLCT transition band with different

degree of red-shift from the MLCT transition band of the the mononuclear complex 20.

The �max of such band is in an increasing order of 16 (Pt���Hg, 406 nm) < 14 (Pt���Ag, 385

nm) < 15 (Pt���Cu, 454 nm) < 13 (Pt���Au, 461 nm) < 17 (Pt���Rh, 501 nm), probably

indicating a same trend of the strength of metal-metal interaction in these dinulear

complexes in solution. However, for the complexes of Pt-Cu (15) and Pt-Rh (17), such a

red-shift may be also partially from the contribution of the metal-alkynyl �-bonding, as �-

coordination of the FcC�C group to CuI or RhI will result in the lowering of the

109

�*(C�CFc) orbital energy. Similar effect was proposed for the tetranuclear mixed-metal

complex [Pt2(C�CPh)2(�-dppm)2�{Cu(CH3CN)}2](PF6)2, where each CuI is �-coordinated

to two PhC�C groups.109

6.2.4 Electrochemistry

The electronic properties of complexes 13-17 and 20 were gauged by voltammetric

techniques (complexes 12, 18 and 19 are not stable in solution and therefore not

investigated). Osella and coworkers have reported the cyclic voltammogram (CV) of the

mononuclear complex trans-Pt(C�CFc)2(PPh2Me)2 (20) in THF solution.91 Their study

showed that there was very poor electronic coupling (�E1/2 = 80 mV, Kc = 23) between

two Fc centers in the mixed-valence state 20+. For comparison, we remeasured the CV of

complex 20 in CH2Cl2, which is a more suitable solvent than THF for our system. The

anodic sweep produce two reversible oxidation waves (Figure 6.13a) overlapped at ca. -

60 mV vs FcH+/FcH (all potentials measured in this study are referred to FcH+/FcH),

which are attributed to the successive oxidations of the two Fc groups in the molecule of

20. Such two peaks located at -91 and -37 mV are better resolved in the differential pulse

voltammogram (DPV) (Figure 6.13b). The splitting of the reduction potentials of two Fc

group (�E1/2) is 54 mV, which is slightly smaller than the reported value (80 mV)

measured in THF.91 From Equation 5.1, the comproportionation constant (Kc) of the

mixed-valence state 20+ is found to be 8 (smaller than that of 23 in THF91). The decrease

of �E1/2 and Kc indicates that the electronic coupling between two Fc centers in the

mixed-valence state 20+ is even weaker in CH2Cl2 than in THF. The CVs of the dinuclear

species of 13-17 were measured under the same condition as that of 20 (Figure 6.14-

6.18). For the complexes 13 (Pt-Au) and 14 (Pt-Ag), DPVs were also measured in order

110

-600 -400 -200 0 200 400 600-8

-6

-4

-2

0

2

4

6

8

10

B'

A'

B

A

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

-400 -200 0 200 4000

1

2

3

4

5 BA

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

(a)

(b)

Figure 6.13 (a) CV of complex 20 at room temperature. Solvent: CH2Cl2 (0.1 M tetrabutylammonium hexafluorophosphate (TBAH)); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 1 mM; scan rate: 100 mV/s; (b) DPV of complex 20 at room temperature. Solvent: CH2Cl2 (0.1M TBAH), working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1M CH3CN); sample concentration: 1 mM; scan rate: 20mV/s.

111

-600 -400 -200 0 200 400 600-4

-2

0

2

4

6

B'

A'

BA

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

-400 -200 0 200 4000

1

2

3

4

5

6 BA

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

(a)

(b)

Figure 6.14 (a) CV of complex 13 at room temperature. Solvent: CH2Cl2 (0.1 M tetrabutylammonium hexafluorophosphate (TBAH)); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 1 mM; scan rate: 100 mV/s; (b) DPV of complex 13 at room temperature. Solvent: CH2Cl2 (0.1M TBAH), working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1M CH3CN); sample concentration: 1 mM; scan rate: 20mV/s.

112

-600 -400 -200 0 200 400 600-6

-4

-2

0

2

4

6

8

B'

A'

B

A

Cur

rent

, µA

Potential, mV vs FcH+/FcH

-400 -200 0 200 4000

1

2

3

4

5

6 BA

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

(a)

(b)

Figure 6.15 (a) CV of complex 14 at room temperature. Solvent: CH2Cl2 (0.1 M tetrabutylammonium hexafluorophosphate (TBAH)); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 1 mM; scan rate: 100 mV/s; (b) DPV of complex 14 at room temperature. Solvent: CH2Cl2 (0.1M TBAH), working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1M CH3CN); sample concentration: 1 mM; scan rate: 20mV/s.

113

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

-3

-2

-1

0

1

2

3

4

B'

A'

B

A

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

Figure 6.16 CV of complex 15 at room temperature. Solvent: CH2Cl2 (0.1 M TBAH); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 0.3 mM; scan rate: 100 mV/s.

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

-4

-2

0

2

4

6

B'A'

B

A

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

Figure 6.17 CV of complex 16 at room temperature. Solvent: CH2Cl2 (0.1 M TBAH); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 0.3 mM; scan rate: 100 mV/s.

114

to get better resolution (Figure 6.14b and 6.15b). Each of them shows two reversible

oxidation waves in the anodic sweep, due to the successive oxidations of the two Fc

groups in each molecule of these complexes. Their electrochemical data are summarized

in Table 6.6. The results show that the reduction potentials corresponding to the first Fc

oxidation are in a sequence of 16 (Pt-Hg, -105 mV) < 20 (-91 mV) << 14 (Pt-Ag, -27 mV)

< 15 (Pt-Cu, -17 mV) < 13 (Pt-Au, -16 mV) < 17 (Pt-Rh, 18 mV). Such a sequence could

be explained by the combination of electrostatic effect, metal-metal interaction and

metal-ligand interaction. Complexes 16 and 20 are neutral species, while the other four

complexes are salts and therefore exist as cations in solution. As a result, the Fc groups in

complexes of 13-15 and 17 more or less feel an additional positive charge and become

much less reducing compared to those in the neutral complexes 16 and 20. Compared to

the mononuclear complex 20, 16 possess electron richer Pt centers due to the presence of

-1000 -800 -600 -400 -200 0 200 400 600 800 1000

-3

-2

-1

0

1

2

3

4

5

B'A'

B

A

Cur

rent

, µA

Potential, mV vs. FcH+/FcH

Figure 6.18 CV of complex 17 at room temperature. Solvent: CH2Cl2 (0.1 M TBAH); working electrode: glassy carbon (0.07 cm-2); counter electrode: platinum wire; reference electrode: Ag/AgNO3 (0.1 M CH3CN); sample concentration: 0.3 mM; scan rate: 100 mV/s.

115

E1/2 (1st Fc oxidation, mV)a

E1/2 (2nd Fc oxidation, mV)a

�Ep (mV)b

�E1/2

(mV) Kcc

20 -91 -37 54 8 13 (Pt-Au) -16 16 32 3 14 (Pt-Ag) -27 54 81 23 15 (Pt-Cu) -17 117 70 134 185 16 (Pt-Hg) -105 39 69 144 272 17 (Pt-Rh) 18 228 65 210 3560

metal-metal interaction. Hence, via �-back donation from d� of Pt to the �*-orbital of the

C�C bond which is conjugated with the �-orbital of the Cp ring, the order of electron

richness of a Pt center (16 > 20) leads to a similar trend of electron density on the Fc

group. Compared to complexes 13 (Pt-Au), 15 (Pt-Cu) and 17 (Pt-Rh), where there is no

coordination between the corresponding anion (ClO4- or PF6

-) and cation (metal moieties)

in the crystals, complex 14 (Pt-Ag) may a bit less completely dissociate to free ions in

solution, as there is weak coordination between anion (NO3-) and cation (Ag+) in the

crystal of complex 14. Therefore, due to electrostatic effect, the Fc groups in 14 are more

reducing than those in 13, 15 and 17, despite that the metal-metal interaction (from UV-

vis absorption spectra) in 14 is weaker than that in the other three complexes. Compared

to complexes 13 and 15, complex 17 possesses much less reducing Fc groups. This is

probably related to the �-coordination between Rh and C�C in 17, which is absent in

complex 13 and weaker in complex 15 (between Cu and C�C). Due to electron

withdrawing from C�C by Rh through such �-bond, the electron density of the �-

Table 6.6 Electrochemical data of complexes 13-17 and 20

a The half-wave potential (E1/2) values are the average of the cathodic and anodic peak potentials for the oxidative and reductive waves of reversible couples; b �Ep denotes the difference between the cathodic and anodic peak potentials for the oxidative and reductive waves of each reversible couple; c Kc was calculated from Equation 5.1,

Kc = e

F___RT �E1/2

116

coordinated FcC�C group is much reduced, while that of the non-�-coordinated FcC�C

group is relatively little reduced and become the first to be oxidized. However, the

electrochemical data show that such an indirect reduction of electron density on the non-

�-coordinated FcC�C group is drastic enough to make the Fc center in 17 less reducing

than those in 13 and 15.

The extent of electronic communication between the two Fc centers in the mixed-

valence state of these complexes could be qualitatively judged by the comparison of

�E1/2 or Kc. The values of �E1/2 of all these complexes are in an order of 13 (Pt-Au, 32

mV) < 20 (54 mV) < 14 (Pt-Ag, 81 mV) < 15 (Pt-Cu, 134mV) < 16 (Pt-Hg, 144mV) < 17

(Pt-Rh, 210mV), indicating a same trend of the degree of electronic communication

between the two Fc groups in them. However, for complexes 15 and 17, the relatively

large values of �E1/2 can not be expressed as a real relative great electronic

communication between the two Fc centers, as the two FcC�C groups in these two

complexes are chemical inequivalent due to the �-coordination between metal and one of

the two C�C bonds. It is not possible to separate the combined effects of chemical

inequivalence and electronic communication to determine the relative contribution of

each factor to the total. Similar suggestion has been made on the unsymmetrical

complexes of Os3(CO)10(�3-FcC�CC�CFc)111 and PtOs3(CO)9(COD)(�4-

FcC�CC�CFc)112 (COD = 1, 5-cyclooctadiene). For the two neutral complexes (20 and

16), the electronic communication in 16 is much greater than that in 20 (Kc of 16+ is more

than 20 times as that of 20+). This may be attributed to the increased electron density on

the Pt center via Pt���Hg interaction, which may enhance the degree of electron

delocalization along the Fc-C�C-Pt-C�C-Fc backbone by the interaction of the d� orbital

117

of Pt and the �* orbital of the alkynyl group. In contrast, the Pt���Au and Pt���Ag

interactions in complexes 13 and 14, respectively, which seem stronger than Pt���Hg

interaction (from UV-vis spectra), do not lead to much enhancement of electronic

communication between two Fc groups compared to that in the mononuclear complex 20.

This is most likely due to the electrostatic effect that is mentioned above. As both 13 and

14 are ionic in nature (especially 13), the Pt���Au/Ag moiety is positive-charged in

solution. Upon oxidation of one of the two Fc centers, the other one can hardly ‘feel’ the

charge of the oxidized one due to the shielding effect from the positive Pt���Au/Ag moiety

which is the center of the bridge between the two redox active termini. Therefore, the

electronic communication between two Fc groups in 13 and 14 are very poor.

6.3 Conclusions

In this part of study, the redox-active ferrocenyl group was successfully introduced to a

series of hetero-bimetallic platinum(II) complexes by Shaw’s methods.101 Crystal

structures of dinuclear complexes 14-19 indicate the presence of metal-metal interactions

in solid state. While the instabilities of complexes 12, 18 and 19 in solution prohibited the

investigation of their electronic absorption spectroscopy and electrochemical properties,

behaviors of complexes 13-17 and 20 in solution were examined via UV-vis absorption

spectra and voltammetric techniques. UV-visible spectroscopic studies prove that metal-

metal interactions exist in solution for complexes 13-17. The electrochemical data show

that Pt���Hg interaction in complex 16 can enhance the electron delocalization along the

C�C-Pt-C�C bridge. The effect of Pt���Cu/Rh interaction on the electronic

communication between two Fc centers in complex 15 or 17 could be hardly estimated

from the electrochemical data, due to the fact that the asymmetry of 15 or 17 may

118

contribute significantly to the splitting between the reduction potentials of the first and

second Fc oxidations. As some extent of positive charge is introduced to the C�C-Pt-

C�C bridge in complexes 13 and 14, the electronic communication between two Fc

centers may be prohibited due to the electrostatic effect. To further check the correctness

of this suggestion, an investigation of the counter ion effect on the electronic

communication is worth carrying out based on the Pt���Ag system, as different anions

possess different abilities of coordinating to AgI. On the whole, our results indicate that

the metal-metal interaction in this system may be too weak to provide efficient conduit in

electronic communication.

6.4 Experimental section

All reactions were carried out using standard Schlenck techniques. PPh2Me, dppm, n-

butyllithium (1.6 M in hexane), AgNO3, LiClO4, CuI, NH4PF6, HgCl2, trans-

(Ph3P)2Rh(CO)Cl, fac-W(CO)3(CH3CN)3 and fac-Mo(CO)3(CH3CN)3 purchased from

Aldrich and KAuCl4�xH2O, PtCl2 purchased from Oxkem were used without further

purification. The supporting electrolyte tetra-n-butylammonium hexafluorophophate

(TBAH) obtained from Aldrich was recrystallized from ethanol and dried at 100 ºC for

24 h before used. All solvents used for syntheses and spectroscopic measurements were

purified according to literature methods. FcC�CH113 and [Cu(CH3CN)4]PF6114

were

synthesized by literature methods. Ph3PAuCl was prepared by reacting of 2 molar equiv.

of PPh3 with KAuCl4�xH2O in methanol. Pt(CH3CN)2Cl2 was prepared by refluxing PtCl2

in large excess of CH3CN. Pt(PPh2Me)2Cl2 and Pt(µ-dppm)Cl2 were prepared by reacting

of 2 equiv. of PPh2Me and 1 equiv. of dppm, respectively, with Pt(CH3CN)2Cl2 in CH2Cl2.

119

CAUTION! Perchlorate salts of metal complexes with organic ligands are potentially

explosive and should be handled in small quantities with care.

(In the following assignments of 31P{1H}-NMR spectra, PA denotes P atoms coordinated

to Pt, while PB denotes P atoms either uncoordinated (in complex 12) or coordinated to

the metal atom other than Pt (in complexes 13-19).)

trans-Pt(C�CFc)2(�1-dppm)2 (12): 1.500 g (2.31 mmol) of Pt(µ-dppm)Cl2 and 0.885 g

(2.31 mmol) of dppm were added with 20 ml of benzene to a solution of LiC�CFc

(prepared in situ by reaction of 0.985 g (4.71 mmol) of FcC�CH in 60 ml of THF with

2.94 ml (4.71 mmol) of 1.6 M hexane solution of n-butyllithium). The reaction mixture

was then refluxed for 1.5 hours, followed by being stirred at room temperature overnight.

The solvent was then removed under reduced pressure and the residue was recrystallized

from benzene-methanol to give orange crystalline. Yiled: 1.67 g (52%). Anal. Calcd for

C74H62P4Fe2Pt: C, 64.3; H, 4.5. Found: C, 64.8; H, 4.1. 1H NMR (300 MHz, CDCl3,

/ppm): 7.88-7.15 (br, 40H, Ph), 3.86-3.57 (m, 22H, -PCH2P-, C5H4 and C5H5). (There

are several relatively weak signals in this range caused by dissociation of 12 in solution.)

31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 7.91 (PA, 1J(PtPA) = 2598 Hz), -25.78 (PB).

Complex 12 slightly dissociates in solution, as the 31P{1H}-NMR spectrum shows

another three peaks at: 7.44 (unknown decomposition species), 1.47 (Pt2(µ-

dppm)2(C�CFc)4), -22.17 (free dppm). ESI-MS (m/z, assignment): 1173.1 [M − C�CFc]+;

1381.0 [M]+. IR (KBr, (C�C)/cm-1): 2110 (w). Single crystals of 12 for X-ray diffraction

analysis were grown by slow diffusion of methanol into a concentrated toluene solution

of 12.

120

[Pt(C�CFc)2(µ-dppm)2Au](ClO4) (13): 0.150 g (0.109 mmol) of 12 was added to 20 ml

of CH2Cl2 solution of 0.053 g (0.107 mmol) of Ph3PAuCl. After being stirred for 15

minutes, the solution was rota-evaporated to dry. The residue was then extracted by 30 ml

of methanol. And the methanolic filtrate was reduced to a small volume of about 5 ml on

a rota-evaporator. Excess LiClO4 was then added into this solution to form red

precipitates, which were collected by filtration and washed with minimum amount of

methanol. Yiled: 0.14 g (77%). Anal. Calcd for C74H62O4P4ClFe2PtAu: C, 53.0; H, 3.7.

Found: C, 53.0; H, 3.3. 1H NMR (300 MHz, CDCl3, /ppm): 7.93-7.86, 7.78-7.71 and

7.46-7.30 (m, 40H, Ph), 4.48 (br, 4H, -PCH2P-), 3.91 (br, 4H, H2 and H5 of C5H4), 3.78 (s,

10H, C5H5), 3.57 (br, 4H, H3 and H4 of C5H4). 31P{1H}-NMR (121.5 MHz, CDCl3,

/ppm): 30.86 (PB, 3J(PtPB) = 149 Hz, |2J(PAPB) + 4J(PAPB�)| = 50 Hz), 8.23 (PA, 1J(PtPA)

= 2613 Hz, |2J(PAPB) + 4J(PAPB�)| = 50 Hz). ESI-MS (m/z, assignment): 1578.0 [M −

ClO4]+. IR (KBr, (C�C)/cm-1): 2112 (w).

[Pt(C�CFc)2(µ-dppm)2Ag](NO3) (14): 0.250 g (0.181 mmol) of 12 was suspended in 13

ml of acetone. The suspension was warmed to about 40 °C, followed by slow addition of

3 ml of acetone solution of 0.031 g (0.181 mmol) of AgNO3. The mixture was stirred for

about 10 minutes before being rota-evaporated to dry. The residue was recrystallized

from CH2Cl2-Et2O to give dark orange crystalline. Yield: 0.24 g (85%). Anal. Calcd for

C74H62O3P4NFe2PtAg: C, 57.3; H, 4.0. Found: C, 57.4; H, 3.8. 1H NMR (300 MHz,

CDCl3, /ppm): 7.92-7.86, 7.54-7.47 and 7.32-7.13 (m, 40H, Ph), 4.08 (br, 4H, -PCH2P-),

3.86 (t, 4H, H2 and H5 of C5H4), 3.80 (s, 10H, C5H5), 3.56 (t, 4H, H3 and H4 of C5H4).

31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 11.93 (PA, 1J(PtPA) = 2602 Hz, |2J(PAPB) +

4J(PAPB�)| = 80 Hz), -4.46 (PB, 1J (109AgPB) = 549 Hz, 1J(107AgPB) = 458 Hz, 3J(PtPB) =

121

191 Hz, |2J(PAPB) + 4J(PAPB�)| = 80 Hz). ESI-MS (m/z, assignment): 1488.9 [M − NO3]+.

IR (KBr, (C�C)/cm-1): 2106 (w). Single crystals of 14·0.5Et2O for X-ray diffraction

analysis were grown by slow diffusion of diethylether vapor into a concentrated

CH2Cl2/EtOH (v/v = 1:1) solution of 14.

[(FcC�C)Pt(µ-dppm)2(�, �2-C�CFc)Cu](PF6) (15): 0.200 g (0.145 mmol) of 12 was

added to 30 ml of CH2Cl2 solution of 0.053 g (0.145 mmol) of [Cu(CH3CN)4](PF6). After

being stirred for 30 minutes, the solution was filtered and the filtrate was concentrated on

a rota-evaporator. Large excess of diethylether was then added into the concentrated

solution to form red precipitates, which were collected by filtration and washed with

diethylether. Yield: 0.18 g (78%). Anal. Calcd for C74H62CuF6Fe2 P5Pt: C, 55.9; H, 3.9.

Found: C, 56.0; H, 3.1. 1H NMR (300 MHz, CDCl3, /ppm): 7.76-7.30 (m, 40H, Ph),

3.96 (br, 8H, -PCH2P- and H2, H5 of C5H4), 3.81 (br, 10H, C5H5), 3.55 (br, 4H, H3 and

H4 of C5H4). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 12.47 (PA, 1J(PtPA) = 2472 Hz,

|2J(PAPB) + 4J(PAPB�)| = 69 Hz), -6.03 (PB, 3J(PtPB) = 225 Hz, |2J(PAPB) + 4J(PAPB�)| = 69

Hz), -143.99 (sept, PF6-) . ESI-MS (m/z, assignment): 1445.0 [M − PF6]+. IR (KBr,

(C�C)/cm-1): 2118 (br, w, uncoordinated to Cu), 2074 (br, w, coordinated to Cu). Single

crystals of 15·1.5CH2Cl2 for X-ray diffraction analysis were grown by slow diffusion of

diethylether vapor into a concentrated CH2Cl2/EtOH (v/v = 1:1) solution of 15.

Pt(C�CFc)2(µ-dppm)2HgCl2 (16): similar to the preparation of 15 except that

[Cu(CH3CN)4](PF6) was replaced by HgCl2. Yield: 77%. Anal. Calcd for

C74H62P4Cl2Fe2PtHg: C, 53.8; H, 3.8. Found: C, 53.9; H, 3.3. 1H NMR (300 MHz, CDCl3,

/ppm): 8.15-8.08, 7.84-7.78, 7.35-7.28 and 7.16-7.11 (m, 40H, Ph), 4.31 (br, 4H, -

PCH2P-), 3.86 (t, 4H, H2, H5 of C5H4), 3.82 (s, 10H, C5H5), 3.52 (t, 4H, H3 and H4 of

122

C5H4). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 16.33 (PB, 1J(HgPB) = 5516 Hz,

3J(PtPB) = 259 Hz, |2J(PAPB) + 4J(PAPB�)| = 69 Hz), 10.86 (PA, 1J(PtPA) = 2663 Hz,

|2J(PAPB) + 4J(PAPB�)| = 69 Hz). ESI-MS (m/z, assignment): 1618.7 [M − Cl]+. IR (KBr,

(C�C)/cm-1): 2107 (br, w). Single crystals of 16·1.5CH2Cl2 for X-ray diffraction analysis

were grown by slow diffusion of diethyletherl vapor into a concentrated CH2Cl2/EtOH

(v/v = 1:1) solution of 16.

[(FcC�C)Pt(µ-dppm)2(�, �2-C�CFc)Rh(CO)](PF6) (17): similar to the preparation of 13

except that Ph3PAuCl and LiClO4 were replaced by trans-(Ph3P)2Rh(CO)Cl and NH4PF6

respectively and reaction time was elongated to one hour. Yield: 50%. Anal. Calcd for

C75H62OP5F6Fe2PtRh: C, 54.3; H, 3.8. Found: C, 54.8; H, 3.3. 1H NMR (300 MHz,

CDCl3, /ppm): 8.09-8.02, 7.88-7.76 and 7.57-7.13 (m, 40H, Ph), 4.39 (sept, 2H, He of -

PCH2P-), 4.09 (br, 2H, Ha of -PCH2P-), 4.03 (t, 2H, H2, H5 of C5H4 from FcC�C-

coordinated to Rh), 3.87 (br, 2H, H2, H5 of C5H4 from FcC�C- uncoordinated to Rh),

3.76 (s, 5H, C5H5 from FcC�C- coordinated to Rh), 3.71 (s, 5H, C5H5, from FcC�C-

uncoordinated to Rh), 3.68 (t, 2H, H3, H4 of C5H4 from FcC�C- coordinated to Rh), 3.61

(br, 2H, H3, H4 of C5H4 from FcC�C- uncoordinated to Rh). 31P{1H}-NMR (121.5 MHz,

CDCl3, /ppm): 20.19 (PB, 1J(RhPB) = 114 Hz, |2J(PAPB) + 4J(PAPB�)| = 50 Hz), 4.74 (PA,

1J(PtPA) = 2457 Hz), -145.03 (sept, PF6-). ESI-MS (m/z, assignment): 1511.9 [M − PF6]+.

IR (KBr, cm-1): (C�C), 2026 (br, w); (C�O), 1967 (s). Single crystals of

17·0.75CH2Cl2 for X-ray diffraction analysis were grown by slow diffusion of

diethylether into a concentrated CH2Cl2/EtOH (v/v = 1:1) solution of 17.

(FcC�C)Pt(µ-dppm)2(µ-C�CFc)W(CO)3 (18): 0.047 g (0.12 mmol) of fac-

W(CO)3(CH3CN)3 was added into 30 ml of benzene solution of 0.165 g (0.12 mmol) of

123

12. The solution was stirred under reflux for 2 hours. After being cooled to room

temperature, the resultant solution was filtered and the filtrate was rota-evaporated to dry.

The residue was recrystallized from toluene-(n-hexane) to give red crystalline. Yield:

0.059g (30%). Anal. Calcd for C77H62O3P4Fe2PtW: C, 56.1; H, 3.8. Found: C, 56.2; H,

3.4. 1H NMR (300 MHz, CDCl3, /ppm): 7.95-7.14 (br, 40H, Ph), 3.90 (br, 10H) and

3.74 (s, 12H) (-PCH2P-, C5H4, C5H5 and probably including some decomposition

components which could not be assigned separately). 31P{1H}-NMR (121.5 MHz, CDCl3,

/ppm): 14.85 (PB, 3J(PtPB) = 305 Hz, |2J(PAPB) + 4J(PAPB�)| = 72 Hz), 2.98 (PA, 1J(PtPA)

= 2586 Hz, |2J(PAPB) + 4J(PAPB�)| = 72 Hz). ESI-MS (m/z, assignment): 1648.2 [M]+. IR

(KBr, cm-1): (C�C), 2118 (br, w); (C�O), 1953 (m). Single crystals of 18·toluene·n-

hexane for X-ray diffraction analysis were grown by slow diffusion of n-hexane into a

concentrated toluene solution of 18.

(FcC�C)Pt(µ-dppm)2(µ-C�CFc)Mo(CO)3 (19): similar to the preparation of 18 except

that fac-W(CO)3(CH3CN)3 was replaced by fac-Mo(CO)3(CH3CN)3 and the

recrystallization solvent system was changed to THF-(n-hexane). Yield: 15%. Anal.

Calcd for C77H62O3P4Fe2PtMo: C, 59.2; H, 4.0. Found: C, 59.1; H, 3.8. 1H NMR (300

MHz, CDCl3, /ppm): 8.04-7.95 and 7.60-7.01 (m, 40H, Ph), 4.03-3.61 (m, 22H, -

PCH2P-, C5H4 and C5H5, including some decomposition components which could not be

assigned separately). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 36.80 (PB, |2J(PAPB) +

4J(PAPB�)| = 65 Hz), 2.83 (PA, 1J(PtPA) = 2617 Hz, |2J(PAPB) + 4J(PAPB�)| = 65 Hz). (There

is a doublet of doublets at 12.69 ppm due to a decomposition species.) IR (KBr, cm-1):

(C�C), 2107 (br, w); (C�O), 1953 (br, w). Single crystals of 19·1.9THF for X-ray

124

diffraction analysis were grown by slow diffusion of n-hexane into a concentrated THF

solution of 19.

trans-Pt(C�CFc)2(PPh2Me)2 (20): 0.333 g (0.50 mmol) of cis-Pt(PPh2Me)2Cl2 was

added to 20 ml of HNEt2 containing 0.252 g (1.20 mmol) of FcC�CH and 0.019 g (0.10

mmol) CuI. The mixture was refluxed for half an hour. Upon cooling to room

temperature, the product was filtered off and washed with ethanol. No further purification

was required. Yield: 0.43 g (85%). Anal. Calcd for C50H44Fe2P2Pt: C, 59.2; H, 4.4. Found:

C, 59.1; H, 4.2. 1H NMR (300 MHz, CDCl3, /ppm): 7.90-7.85 and 7.45-7.43 (m, 20H,

Ph), 3.91-3.90 (m, 14H, H2 and H5 of C5H4 and C5H5), 3.85 (t, 4H, H3 and H4 of C5H4),

2.40 (m, 6H, CH3). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 0.03 (1J(PtP) = 2564 Hz).

ESI-MS (m/z, assignment): 1013.0 [M]+. IR (KBr, (C�C)/cm-1): 2114 (br, w). Single

crystals of 20 for X-ray diffraction analysis were grown by slow diffusion of EtOH into a

concentrated CH2Cl2 solution of 20.

125

Chapter 7

Synthesis and Photophysical Studies of a Series of Platinum(0)-

acetylene Complexes

126

7.1 Introduction

In 1957, Chatt and coworkers first prepared platinum(0)-acetylene � complexes of the

type (PPh3)2Pt(RC�CR), suggesting that the acetylene in these complexes was coplanar

with the two P atoms and the Pt atom.115 Ten years later, that prediction was proved to be

correct by the determination of the crystal structure of (PPh3)2Pt(PhC�CPh) by Grim and

coworkers.116a Since then, a good many of crystallographic studies of this type of

complexes have been carried out.99a, 99b, 116, 117 The phosphine ligand used could be either

monodentate like PPh3, PMe3116f and PCy3

116d (tricyclohexylphosphine), or bidentate

such as dppp117c (1, 3-bis(diphenylphino)propane) and dppf116i (1, 1�-

bis(diphenylphosphino)ferrocene). And the acetylenes investigated were not only

monoacetylenes but also diacetylenes116i, 117b, 117c and even cyclic acetylenes such as

cyclohexyne and cycloheptyne.116c, 116g The nature of the bonding in this type of

platinum(0)-acetylene complexes has been the subject of a number of theoretical

studies.118, 119 For example, Nelson and coworkers developed a dp2 metal hybridization

scheme to explain the chemical and physical properties of these complexes, based on

semiempirical one-electron molecular orbital calculations.118b In addition, this type of

complexes have been reported to possess good reactivity in various organometallic

reactions.117, 120 For instance, the reaction between the complex (PPh3)2Pt(acetylene) and

protonic acids HX has been found to yield complexes of general formula (PPh3)2PtX2 and

the corresponding olefin, which were considered as a means of reducing acetylenes to

olefins.120 However, the electronic spectroscopic studies of this type of complexes are

relatively sparse.99 In particular, as far as we know, the luminescent properties of this

type of complexes have been reported only once.99a As is mentioned in Chapter 5, the

127

objective of this part of my work was to investigate the electronic absorption and

emission properties of a series of this type of complexes. The structures of target

molecules are shown in Figure 7.1.

Ph Ph

Pt

Ph3P PPh3

Pt

P P

R R

R R

Pt

PP

Pt

P P

Pt

P P

Ph Ph

Ph

Pt

Ph3P PPh3

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

Ph

PhPh

Ph

Pt(PPh3)2(PhC2Ph) Pt(dppp)(PhC2Ph)

R = Ph: Pt(dppp)(PhC4Ph), (24);R = CH3: Pt(dppp)(CH3C4CH3), (26)

Pt(PPh3)2(PhC4Ph)

R = Ph: (Pt(dppp))2(PhC4Ph), (25);R = CH3: (Pt(dppp))2(CH3C4CH3), (27)

(21) (22)

(23)

Figure 7.1 Structures and nomenclatures of target complexes in this charpter.

128

7.2 Results and discussion

7.2.1 Synthesis and characterization

There are two methods in literatures for preparing Pt0 acetylene complexes.121 The first

method121a involves reduction of PtII by hydrazine (N2H4) in the presence of acetylene

ligand in alcohol. In this work, mononuclear complexes Pt(PPh3)2(PhC2Ph) (21) and

Pt(PPh3)2(PhC4Ph) (23) were synthesized by this method, while complexes

Pt(dppp)(PhC2Ph) (22) and Pt(dppp)(PhC4Ph) (24) could not be obtained by exactly the

same method. However, upon changing the reductant from N2H4 to NaBH4, we

successfully prepared complexes 22 and 24. This may be explained by the fact that

stronger electron donating property of dppp than that of PPh3 makes PtII centers more

electron rich and therefore a stronger reductive is required to reduce PtII to Pt0. However,

the first method is not applicable for preparing binuclear complexes of diacetylene ligand,

as the reaction requires the stepwise complexation of Pt0 to the acetylene and the poor

solubility in alcohol of the mononuclear complexes prohibits the second �-coordination.

The second method121b involves replacement of ethylene by acetylene via the reaction

between (R3P)2Pt(C2H4) and the acetylene ligand in ether. This method has been proved

efficient for preparing both mononuclear and binuclear complexes of diacetylene ligand.

Complex Pt(dppp)(CH3C4CH3) (26) and the dinuclear species (Pt(dppp))2(PhC4Ph) (25)

and (Pt(dppp))2(CH3C4CH3) (27) were synthesized by this method.

The ESI-MS spectra of complexes 21-27 all show distinct peaks attributable to the

corresponding molecular ion M+. The IR spectra of the monoacetylene complexes

Pt(PPh3)2(PhC2Ph) (21) and Pt(dppp)(PhC2Ph) (22) show weak signals at 1741 and 1748

cm-1 respectively, assigned to stretching of the coordinated C�C bonds. And the IR

129

spectra of the mononuclear complexes of diacetylene ligands Pt(PPh3)2(PhC4Ph) (23),

Pt(dppp)(PhC4Ph) (24) and Pt(dppp)(CH3C4CH3) (26) show two resonance signals at

1719-1749 and 2160-2196 cm-1 due to the stretching of coordinated and uncoordinated

C�C bonds, respectively. Only one of these two peaks is observed at 1758 and 1705 cm-1

in the IR spectra of the dinuclear complexes (Pt(dppp))2(PhC4Ph) (25) and

(Pt(dppp))2(CH3C4CH3) (27), respectively, indicating that both C�C bonds are attached

to metal atoms. The 31P{1H}-NMR spectra of complexes 21 and 22 show only a triplet at

27.07 and 4.11 ppm with 1J(PtP) of 3448 and 3155 Hz, respectively. This indicates that

two P atoms in 21 and 22 are symmetric in solution. On the contrary, as two P atoms in

complex 23 are not chemically equivalent, the 31P{1H}-NMR spectrum of complex 23

shows two doublets of triplets at 26.53 and 26.19 ppm, with 2J(PP) of 22.9 Hz. And two

corresponding values of 1J(PtP) are 3521 and 3456 Hz, respectively. This is in line with

the pattern of a typical AB system. The 31P{1H}-NMR spectrum of complexes 24 and 26

shows a similar pattern. The 31P{1H}-NMR spectrum of dinuclear complexes

(Pt(dppp))2(PhC4Ph) (25) and (Pt(dppp))2(CH3C4CH3) (27) should be the pattern of a

[AB]2 system which is similar to spectra of complexes 23, 24 and 26. However, the

31P{1H}-NMR spectrum of complex 25 does not show a well resolved pattern of two

doublets of triplets, which is due to the fact that the chemical shifts of the two P atoms on

each Pt centre are too close to be well resolved (4.18 and 3.94 ppm, 2J(PP) = 26.7 Hz).

Two different values of 1J(PtP) are observed (3258 and 3267 Hz). And the 31P{1H}-NMR

spectrum of complex 27 is so unresolved that the chemical shifts of the two P atoms on

each Pt centre merge at 8.54 ppm without shown a clear value of 2J(PP) and the two

values of 1J(PtP) are also quite close to each other (3227 and 3258 Hz).

130

7.2.2 Crystal structures

The complexes 22, 24 and 25 were characterized by single-crystal X-ray diffraction

analysis, while crystal structures of 21116a and 23117b have been reported previously.

Pt(dppp)(PhC2Ph) (22)

There are two independent molecules 22a and 22b in the unit cell of crystal 2�THF. The

structures of the two molecules are very similar and the structure of 22a is shown in

Figure 7.2. The molecule contains a plane of symmetry perpendicularly bisecting C1-CA.

The length of the C1-C1A bond is 1.301(7) Å, comparing favorably with that of 1.32(9)

Å observed in the PPh3 analogue 21.116a Such a bond is much longer than a standard C�C

bond (ca. 1.2 Å), indicating significant weakening of C�C bond due to �-donation from

the acetylene to the metal with simultaneous �-back donation from the metal to the

Figure 7.2 ORTEP diagram (thermal ellipsoid = 50%) of 22a (for clarity, phenyl rings of dppp are in thin line format; H atoms and solvent molecules are omitted; C3 and C3X represent two positions of that disordered carbon atom, with 0.4 and 0.1 occupancy respectively.)

131

acetylene. The Pt centre adopts typical planar coordination geometry of platinum(0)-

acetylene �-complexes, with a small dihedral angle of 2.98° between the two triangles of

C1-Pt1-C1A and P1-Pt1-P1A. The Pt-C bond length of 2.041(3) Å and Pt-P bond length

of 2.2705(9) Å are also normal. Like the case in 21,116a the C2-C1�C1A-C2A backbone

is dramatically bent, the C2-C1-C1A angle being 144.5(2)°. The selected bond lengths

and angles are listed in Table 7.1.

Pt(dppp)(PhC4Ph) (24)

Figure 7.3 shows the molecular structure of complex 24. The lengths of the coordinated

C�C bond (C1-C2) and uncoordinated one (C3-C4) are 1.299(6) and 1.201(6) Å, in line

with those of 1.305(11) and 1.200(11) Å observed in complex 23,117b respectively. Like

that in 22a, the coordination geometry at the Pt centre in 24 is also nearly planar,

Figure 7.3 ORTEP diagram (thermal ellipsoid = 50%) of 24 (for clarity, phenyl rings of dppp are in thin line format; H atoms and solvent molecules are omitted)

132

22a 24 25 Distances (Å)

Pt1-C1 2.041(3) Pt1-C2 2.043(4) Pt1-C1 2.034(3) Pt1-C1A 2.041(3) Pt1-C1 2.044(4) Pt1-C2 2.051(3) Pt1-P1 2.2705(9) Pt1-P1 2.2629(10) Pt1-P1 2.2478(9) Pt1-P1A 2.2705(9) Pt1-P2 2.2686(10) Pt1-P2 2.2581(9) C1-C1A 1.301(7) C1-C2 1.299(6) Pt2-C4 2.017(3) C1-C2 1.464(5) C1-C5 1.463(6) Pt2-C3 2.063(3) C1A-C2A 1.464(5) C2-C3 1.393(6) Pt2-P3 2.2423(8) C3-C4 1.201(6) Pt2-P4 2.2755(9) C4-C6 1.433(6) C1-C2 1.303(5) C1-C5 1.451(5) C2-C3 1.411(4) C3-C4 1.296(5) C4-C6 1.454(5)

Angles (°) C1A-Pt1-C1 37.2(2) C2-Pt1-C1 37.05(16) C1-Pt1-C2 37.20(13) C1A-Pt1-P1A 113.35(10) C2-Pt1-P1 155.79(13) C1-Pt1-P1 118.33(10) C1-Pt1-P1A 150.47(10) C1-Pt1-P1 118.81(11) C2-Pt1-P1 155.45(10) C1A-Pt1-P1 150.47(10) C2-Pt1-P2 111.48(12) C1-Pt1-P2 150.64(10) C1-Pt1-P1 113.35(10) C1-Pt1-P2 148.40(11) C2-Pt1-P2 113.44(10) P1-Pt1-P1A 96.02(5) P1-Pt1-P2 92.44(4) P1-Pt1-P2 91.00(3) C1A-C1-C2 144.5(2) C2-C1-C5 137.7(4) C4-Pt2-C3 37.02(13) C1A-C1-Pt1 71.42(10) C2-C1-Pt1 71.5(2) C4-Pt2-P3 109.14(10) C2-C1-Pt1 144.0(3) C5-C1-Pt1 150.1(3) C3-Pt2-P3 145.49(10) C1-C1A-C2A 144.5(2) C1-C2-C3 146.7(4) C4-Pt2-P4 154.86(10) C1-C1A-Pt1 71.42(10) C1-C2-Pt1 71.5(2) C3-Pt2-P4 118.57(10) C2A-C1A-Pt1 144.0(3) C3-C2-Pt1 141.3(3) P3-Pt2-P4 95.76(3) C4-C3-C2 174.7(5) C2-C1-C5 138.6(3) C3-C4-C6 176.5(5) C2-C1-Pt1 72.1(2) C5-C1-Pt1 149.3(3) C1-C2-C3 146.8(3) C1-C2-Pt1 70.7(2) C3-C2-Pt1 142.0(3) C4-C3-C2 146.4(3) C4-C3-Pt2 69.6(2) C2-C3-Pt2 144.0(3) C3-C4-C6 138.6(3) C3-C4-Pt2 73.4(2) C6-C4-Pt2 147.6(2)

Table 7.1 Selected interatomic distances and angles in 22a, 24 and 25

133

dihedral angle between triangles of C1-Pt1-C2 and P1-Pt1-P2 being 4.31°. Though the

molecule of 24 does not have a plane symmetry like that of 22a, the two Pt-C and two Pt-

P bond lengths are almost identical, respectively (Pt1-C1, 2.044(4) Å; Pt1-C2, 2.043(4) Å;

Pt1-P1, 2.2629(10) Å; Pt1-P2, 2.2686(10) Å). While the coordinated C5-C1�C2-C3

backbone is bent (C5-C1-C2, 137.7(4)°; C1-C2-C3, 146.7(4)°) like that in 22a, the

uncoordinated C2-C3�C4-C6 backbone is close to linear (C2-C3-C4, 174.7(5)°; C3-C4-

C6, 176.5(5)°).

(Pt(dppp))2(PhC4Ph) (25)

The molecular structure of complex 25 is shown in Figure 7.4. The lengths of two C�C

bonds are 1.303(5) Å (C1-C2) and 1.296(5) Å (C3-C4), similar to those of the �-

coordinated C�C bond in 22a and 24. While the coordination geometry at Pt1 is nearly

planar (dihedral angle between triangles of C1-Pt1-C2 and P1-Pt1-P2: 2.45°), that at Pt2

is more distorted from planar (dihedral angle between triangles of C3-Pt2-C4 and P3-Pt2-

P4: 10.41°). The two �-coordination triangles of C1-Pt1-C2 and C3-Pt2-C4 are in a

staggered conformation, that they are perpendicular to each other with a dihedral angle of

86.01°. Such a conformation is likely due to a steric consideration, as there may be strong

steric repulsions among the phenyl rings in other conformations. This steric consideration

may be also indicated by the observation that the ‘inner’ bonds (near the perpendicular

bisecting plane of C2-C3) of Pt1-C2 (2.051(3) Å), Pt2-C3 (2.063(3) Å), Pt1-P2 (2.2581(9)

Å) and Pt2-P4 (2.2755(9) Å ) are longer than the corresponding ‘outer’ ones of Pt1-C1

(2.034(3) Å), Pt2-C4 (2.017(3) Å), Pt1-P1 (2.2478(9) Å) and Pt2-P3 (2.2423(8) Å),

respectively. Such elongations are likely for reducing steric repulsions between two

neighboring PPh2- groups. Like the case in 22a and 24, the �-coordinated back bones of

134

C5-C1�C2-C3 and C2-C3�C4-C6 are bent (C5-C1-C2, 138.6(3)°; C1-C2-C3, 146.8(3)°;

C2-C3-C4, 146.4(3)°; C3-C4-C6, 138.6(3)°).

7.2.3 Electronic spectroscopy

The UV-visible absorption spectra of complexes Pt(PPh3)2(PhC2Ph) (21),

Pt(dppp)(PhC2Ph) (22) and their corresponding acetylene ligand PhC2Ph are shown in

Figure 7.5. All of them possess intense high energy absorption bands at 250-305 nm

(extinction coefficients � > 104 M-1cm-1), which are attributed to the ligand (acetylene)

centered ��* transition (for the complexes, they may be mixed with the ��* transition

localized on the phenyl rings of the phosphine ligand). And such absorption bands for

both PhC2Ph and complex 21 are vibronic structured with progressions of about 950 cm-1,

which are ascribed to the skeletal vibration mode of phenyl rings. The spectra of

complexes 21 and 22 display a broad low energy tail at 305-400 nm, assigned to the

(a) (b)

Figure 7.4 (a) ORTEP diagram (thermal ellipsoid = 50%) of 25 (for clarity, phenyl rings of dppp are in thin line format; H atoms and solvent molecules are omitted); (b) a side view showing the staggered conformation of 25.

135

metal-to-ligand (Pt��* of acetylene) charge transfer (MLCT) transition, which is absent

in the spectrum of PhC2Ph. Such assignments are based on similar observations for

analogous platinum(0)-acetylene complexes reported previously.99

The absorption spectrum of the ligand PhC4Ph shows a clear vibronic structured band at

270-340 nm with progressions of ca. 2100 cm-1, which are assigned to the symmetric

(C�C) mode (Figure 7.6). Like those of complexes 21 and 22, the absorption spectra of

complexes Pt(PPh3)2(PhC4Ph) (23), Pt(dppp)(PhC4Ph) (24) and (Pt(dppp))2(PhC4Ph) (25)

are also composed of two sets of absorption bands: the intraligand ��* transition at 250-

340 nm and the MLCT transition at 340-425 nm. Compared to those of PhC2Ph, the ��*

transition absorption bands of the free ligand PhC4Ph are red-shifted, with the low energy

250 300 350 400 450 5000

10000

20000

30000

40000

50000

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

PhC2Ph

Pt(PPh3)2(PhC

2Ph) (21)

Pt(dppp)(PhC2Ph) (22)

Figure 7.5 UV-vis absorption spectra of complexes 21, 22 and ligand PhC2Ph in CH2Cl2 at room temperature

136

end of the spectrum extending from ca. 305 nm to ca. 340nm. This is due to the fact that

the �-conjugation system in PhC4Ph is enlarged by one C�C unit than that of PhC2Ph and

therefore reduces the ��* energy gap. Correspondingly, the MLCT transition absorption

bands in complexes of PhC4Ph (23-25) are also red-shifted compared to those in

complexes of PhC2Ph (21 and 22), with the low energy ends of such bands extending

from ca. 400 nm to ca. 425 nm. This indicates the presence of electron delocalization

along the C�C-C�C backbone in the MLCT excited state. For the dinuclear complex

(Pt(dppp))2(PhC4Ph) (25), the absorption intensity in the MLCT transition region roughly

doubles that for the corresponding mononuclear complex Pt(dppp)(PhC4Ph) (24), which

250 300 350 400 450 5000

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

65000

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

PhC4Ph

Pt(PPh3)2(PhC

4Ph) (23)

Pt(dppp)(PhC4Ph) (24)

(Pt(dppp))2(PhC

4Ph) (25)

Figure 7.6 UV-vis absorption spectra of complexes 23, 24, 25 and ligand PhC4Ph in CH2Cl2 at room temperature

137

is in accordance with the fact that there is one more Pt(dppp) moiety present in the

molecule of 25 compared to that of 24.

The absorption spectra of complexes Pt(dppp)(CH3C4CH3) (26), (Pt(dppp))2(CH3C4CH3)

(27) and the ligand CH3C4CH3 are shown in Figure 7.7. Unlike those of PhC2Ph and

PhC4Ph, the spectrum of CH3C4CH3 shows a very weak absorption band in the UV range

(� < 200 M-1cm-1), which is due to two possible reasons. First, the lack of aromatic

moieties in CH3C4CH3 makes its absorption intensity decrease dramatically. Second, as

methyl groups are stronger electron donating substituents than phenyl rings and can not

extend the �-conjugation of the C�C-C�C backbone, the ��* transition absorption of

CH3C4CH3 may occur at a range of much higher energy (� < 250 nm). On the contrary,

300 400 5000

5000

10000

15000

20000

25000

30000

× 50

Ext

inct

ion

coef

ficie

nt (M

-1cm

-1)

Wavelength (nm)

CH3C

4CH

3 (50 times magnified)

Pt(dppp)(CH3C

4CH

3) (26)

(Pt(dppp))2(CH

3C

4CH

3) (27)

Figure 7.7 UV-vis absorption spectra of complexes 26, 27 and ligand CH3C4CH3 in CH2Cl2 at room temperature

138

the spectra of complexes 26 and 27 show much intense absorption bands at 250-350 nm

and 250-400 nm, respectively, though such intensities are less than half of those of their

corresponding analogous complexes 24 and 25. Such absorption bands are assigned to the

mixing of ��* transition localized in the Pt(dppp) moiety with MLCT (Pt��* of

acetylene) transition. Interestingly, the dinuclear complex 27 exhibits moderate

absorption at 350-400 nm, which is absent in the mononuclear complex 26. This can not

be simply explained by the intensity change caused by quantity change of Pt(dppp)

moieties present in these complexes. It is tentatively regarded as a red-shift of the MLCT

transition band from the case for complex 26 to that for complex 27. Similar phenomena

have been observed for dinuclear RuII complexes in which the metal atoms are bridged by

pi-conjugated ligands.122 A common explanation for such a red-shift is that the presence

of two electron withdrawing metal centers would lower the energy of the ligand �*

orbitals more than a single metal center.122

The room temperature solid state emission spectra of complexes 21-25 are shown in

Figure 7.8. All of them display two broad emission bands situated at 400-500 nm and

500-700 nm, respectively. The former one is assigned to intraligand ��* emission of

corresponding acetylenes, as the position of emission maximum is only determined by

the acetylene ligand involved and not affected by change of metal phosphine moiety from

Pt(PPh3)2 to Pt(dppp). For complexes of the acetylene PhC2Ph such emission maximum

is at av. 445 nm (443 nm for 21; 446 nm for 22), whereas for those of PhC4Ph it is at av.

458 nm (457 nm for 23; 459 nm for 24; 458 nm for 25). The red-shift of this ligand-

centered emission from PhC2Ph to PhC4Ph indicates that the ��* energy gap is smaller in

PhC4Ph than in PhC2Ph, which is due to the fact that π-conjugation is more extended in

139

the latter than in the former. The spin parentage of these ��* excited states is very likely

to be singlet, as Stokes shift between absorption and emission are small. This is also

supported by the short lifetime of these excited states (� < 0.1 �s). Unlike the intraligand

1(��*) emission, the low energy emission at 500-700 nm is shifted not only upon change

of acetylenes but also upon change of phosphines. Therefore, the emission at 500-700 nm

should be of MLCT (d(�) of Pt � �* of acetylene) character. This is also based on Juan

and coworkers’ computational study and similar observation of MLCT emissions in

analogous Pt0 acetylene complexes.99a The emission are maximized in an energy-

decreasing order of 21 (562 nm) > 22 (588 nm) > 23 (597 nm) > 24 (617 nm) > 25 (630

400 450 500 550 600 650 7000

1000

2000

3000

4000

2524232221

*

**

*

**

*

*

*

Inte

nsity

(a.u

.)a

Wavelength (nm)

Pt(PPh3)2(PhC

2Ph) (21)

Pt(dppp)(PhC2Ph) (22)

Pt(PPh3)2(PhC

4Ph) (23)

Pt(dppp)(PhC4Ph) (24)

(Pt(dppp))2(PhC

4Ph) (25)

Figure 7.8 Solid state emission spectra of complexes 21-25 at room temperature (a: intensities of the emission maximum in the low energy region (550-700 nm) are normallized to 1000 for comparision; asterisks at ca. 485 nm and 529 nm denote instrumental artifacts.)

140

nm). The MLCT emissions in complexes Pt(PPh3)2(PhC4Ph) (23) and Pt(dppp)(PhC4Ph)

(24) are red-shifted from those in Pt(PPh3)2(PhC2Ph) (21) and Pt(dppp)(PhC2Ph) (22),

respectively. This is consistent with the fact that the �*-orbital of PhC4Ph is lower in

energy than that of PhC2Ph due to higher extent of π-conjugation. In other words, this

indicates that electrons are delocalized along the C�C-C�C strand in the MLCT excited

states of complexes of PhC4Ph. Respective red-shifts of such emission from 21 and 23 to

22 and 24 can be explained by the different electron donating abilities of PPh3 and dppp.

Compared to PPh3, dppp is a stronger electron donating ligand. In consequence, the

platinum atoms in complexes 22 and 24 are electron richer than those in 21 and 23,

respectively. Therefore, d(�) orbitals of Pt0 in 22 and 24 are respectively higher in energy

than those in 21 and 23. Compared to the intraligand 1(��*) excited states, the MLCT

excited states in these complexes are relatively long-lived at room temperature, with

lifetimes being of microsecond magnitude (1.57-3.86 �s). Therefore, they are assigned to

3MLCT excited states. Such assignment is also based on large Stokes shifts between

MLCT absorption and emission. On the contrary to complexes 21-25, complexes

Pt(dppp)(CH3C4CH3) (26) and (Pt(dppp))2(CH3C4CH3) (27) are not emissive in solid

state at room temperature. A possible explanation is that the backbone of ligand

CH3C4CH3 is much more rigid than those of PhC2Ph and PhC4Ph and therefore the

luminescence in complexes 26 and 27 is much easier to be quenched by nonradiative

decay at room temperature. Such a suggestion is supported by the result that solid state

emissions of complexes 26 and 27 are switched on at low temperature. The 77 K solid

state emission spectra of complexes 26 and 27 are shown in Figure 7.9. (In high energy

region (� < 450 nm), the low temperature measurement (both in solid state and frozen

141

solution) of the emission spectra is badly disturbed by noise signals from the instrument.

Therefore, low temperature emissions were only investigated in low energy region (� >

450 nm).) Both emission spectra of 26 and 27 show a broad band at 549 nm (� = 5.10 �s)

and 541 nm (� = 3.25 �s), respectively. Such emissions in 26 and 27 are accordingly

assigned to 3MLCT transition similar to those in complexes 21-25. This 3MLCT emission

in 26 and 27 is largely blue-shifted from that of the analogous complexes 24 and 25 (617

and 630 nm, respectively), which is in accordance with the fact that the �* orbital of

CH3C4CH3 is much higher in energy than that of PhC4Ph due to the stronger electron

donating ability of CH3 than that of Ph and the less extent of �-conjugation in CH3C4CH3

than that in PhC4Ph. All photophysical data are summarized in Table 7.2.

450 500 550 600 650 7000

200

400

600

800

1000

Nor

mal

lized

inte

nsity

(a. u

.)

Wavelength (nm)

Pt(dppp)(CH3C

4CH

3) (26)

(Pt(dppp))2(CH

3C

4CH

3) (27)

Figure 7.9 Solid state emission spectra of complexes 26 and 27 at 77 K

142

absorption emission (in EtOH, frozen at 77K)

emission (solid state at room temperature)

emission (solid state at 77K)

compound �max/nm (�max/M

-

1cm-1)

�max /nm (�/�s)

excited at/nm

�max /nm (�/�s)

excited at/nm

�max /nm (�/�s)

excited at/nm

Pt(PPh3)2(PhC2Ph) (21)

266(37130), 274(36480), 282(38900), 298(28110)

547 (58.32), 594 (59.03) 320 446 (<0.1),

562 (3.86) 320

Pt(dppp)(PhC2Ph) (22)

266(23510), 326(13750)

570 (39.97), 605 (35.69) 320 443 (<0.1),

588 (2.19) 320

Pt(PPh3)2(PhC4Ph) (23) 328(16600) 589 (21.76),

632 (20.45) 330 457 (<0.1), 597 (2.72) 330

Pt(dppp)(PhC4Ph) (24)

252(37810), 330(15700), 366(10800)

/ 330a 459 (<0.1), 617 (1.57) 330

(Pt(dppp))2(PhC4Ph) (25) 329(28530) / 340a 458 (<0.1),

630b 380

Pt(dppp)(CH3C4CH3) (26) 260(14170) 490 (19.00) 345 549 (5.10) 345

(Pt(dppp))2(CH3C4CH3) (27) 319(12780) 518 (29.20) 350 541 (3.25) 350

PhC2Ph 282(44200), 290(32110), 298(35390)

PhC4Ph

260(30960), 274(17810), 290(25300), 308(34720), 330(30060)

CH3C4CH3 251(180)

Table 7.2 Photophysical data of acetylene ligands PhC2Ph, PhC4Ph, CH3C4CH3 and complexes 21-27

a emissions of 24 and 25 in frozen EtOH were measured but not well resolved from background scattering

b lifetime of low energy excited state of 25 in solid state was not determined due to background scattering

143

The emission spectra of complexes 21-23, 26 and 27 in 77 K frozen ethanol are shown

Figure 7.10 and 7.11. Broad 3MLCT emission bands were observed in the range similar

to that observed in solid state spectra. Compared to those in solid state spectra at room

temperature, the low temperature 3MLCT emission are more long-lived, lifetimes being

in range of 19.00-59.03 �s. The emission maxima (�max) for the mononuclear species are

in an energy order of 26 (490 nm) > 21 (547 nm) > 22 (570 nm) > 23 (589 nm), similar to

that observed in the solid state. Accordingly, this trend could be explained by the same

reasons suggested for that in solid state. The �max of the dinuclear complex 27 (518 nm) is

red-shifted from that of the mononuclear complex 26 (490 nm). This is consistent with

their UV-visible absorption spectra.

Figure 7.10 77 K frozen solution emission spectra of complexes 21, 22 and 23 in ethanol

500 600 700 8000

200

400

600

800

1000

Nor

mal

lized

inte

nsity

(a.u

.)

Wavelength (nm)

Pt(PPh3)2(PhC

2Ph) (21)

Pt(dppp)(PhC2Ph) (22)

Pt(PPh3)2(PhC

4Ph) (23)

144

7.3 Conclusions

In this part of my study, MLCT phosphorescence of a series of phosphine-platinum(0)-

acetylene complexes in both solid state and frozen solution was observed. The results

indicate that there may be substantial electron delocalization along the C4 chain in the

MLCT excite states of complexes 23-25. And the wavelength of the MLCT emission

maximum (�max) is readily tunable by modifying the electron donating ability of either the

ancillary phosphine ligand on Pt or the terminal substituent on the acetylene ligand.

Future work on this part of study may involve introducing another low-lying emissive

moiety such as a polypyridine-RuII fragment to one of the two termini of the Cn chain in

this type of complexes to see whether it can serve as a photonic wire by forming internal

energy transfer between the two emissive moieties in the photo-excited state.

Figure 7.11 77 K frozen solution emission spectra of complexes 26 and 27 in ethanol

450 500 550 600 650 7000

200

400

600

800

1000

1200

Nor

mal

lized

inte

nsity

(a. u

.)

Wavelength (nm)

Pt(dppp)(CH3C

4CH

3) (26)

(Pt(dppp))2(CH

3C

4CH

3) (27)

145

7.4 Experimental section

All reactions were carried out using standard Schlenck techniques. 1, 4-

diphenylbutadiyne, PPh3, dppp, NaBH4 and N2H4�H2O purchased from Aldrich, 2, 4-

hexadiyne purchased from TCI and PtCl2 purchased from Oxkem were used without

further purification. Diphenylacetylene and ethylene were provided by Dr. Leong Weng

Kee. All solvents used for syntheses and spectroscopic measurements were purified

according to literature methods. Pt(CH3CN)2Cl2 was prepared by refluxing PtCl2 in large

excess of CH3CN. Pt(PPh3)2Cl2 and Pt(dppp)Cl2 were prepared by reacting of 2 equiv. of

PPh3 and 1 equiv. of dppp, respectively, with Pt(CH3CN)2Cl2 in CH2Cl2.

Pt(dppp)(CH2=CH2) was prepared by reduction of Pt(dppp)Cl2 in the presence of

ethylene in ethanol.

Pt(PPh3)2(PhC2Ph) (21): 0.20 g (0.25 mmol) of Pt(PPh3)2Cl2 was suspended in 30 ml of

ethanol. 0.2 ml (0.38 mmol) of N2H4�H2O was then added dropwise into the above

suspension. After being stirred for a few minutes, the mixture became a clear light yellow

solution. Then 10 ml ethanolic solution of 0.060 g (0.30 mmol) of diphenylacetylene was

transferred into the reaction solution via cannula. The above mixture was then heated at

reflux for 1 hour to form light yellow precipitate. After being cooled to room temperature,

the precipitate was collected by filtration, washed with excess ethanol and dried in

vacuum. The final product was light yellow powder and required no further purification.

Yield: 0.21 g (93%). Anal. Calcd for C50H40P2Pt: C, 66.9; H, 4.5. Found: C, 66.6; H, 4.4.

1H NMR (300 MHz, CDCl3, /ppm): 7.37-6.83 (m, 40H, Ph). 31P{1H}-NMR (121.5 MHz,

CDCl3, /ppm): 27.07 (1J(PtP) = 3448 Hz). IR (KBr, (C�C)/cm-1): 1741 w. ESI-MS

(m/z, assignment): 897.9 [M]+.

146

Pt(dppp)(PhC2Ph) (22): 0.26 g (0.39 mmol) of Pt(dppp)Cl2 was added into 30 ml

ethanolic solution of 0.085 g (0.42 mmol) of diphenylacetylene to form a white

suspension. Then 0.1 g (2.6 mmol) of NaBH4 was added into the above mixture to form a

light yellow suspension immediately. The reaction mixture was stirred overnight at room

temperature. The yellow solid was collected by filtration and washed with excess ethanol.

Analytical pure product was obtained by recrystallization in THF/n-hexane. Yield: 0.25 g

(80%). Anal. Calcd for C41H36P2Pt: C, 62.7; H, 4.6. Found: C, 62.5; H, 4.5. 1H NMR (300

MHz, CDCl3, /ppm): 7.66-6.96 (m, 30H, Ph), 2.61-2.58 (m, 4H, -CH2-P-Pt-), 2.05-1.91

(m, 2H, -C-CH2-C-). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 4.11 (1J(PtP) = 3155

Hz). IR (KBr, �(C�C)/cm-1): 1748 w. ESI-MS (m/z, assignment): 786.1 [M]+. Single

crystals of 22�THF for x-ray diffraction analysis were obtained by slow diffusion of n-

hexane into a concentrated THF solution of 22.

Pt(PPh3)2(PhC4Ph) (23): the procedures were similar to those for preparing 21. Yield:

90%. Anal. Calcd for C52H40P2Pt: C, 67.7; H, 4.4. Found: C, 67.5; H, 4.3. 1H NMR (300

MHz, CDCl3, /ppm): 7.44-6.88 (m, 40H, Ph). 31P{1H}-NMR (121.5 MHz, CDCl3,

/ppm): 26.53 (2J(PP) = 22.9 Hz, 1J(PtP) = 3521 Hz), 26.19 (2J(PP) = 22.9 Hz, 1J(PtP) =

3456 Hz). IR (KBr, (C�C)/cm-1): 2161 m (uncoordinated), 1721 w (coordinated). ESI-

MS (m/z, assignment): 922.0 [M]+.

Pt(dppp)(PhC4Ph) (24): the procedures were similar to those for preparing 22. Yield:

70%. Anal. Calcd for C43H36P2Pt: C, 63.8; H, 4.5. Found: C, 63.9; H, 4.3. 1H NMR (300

MHz, CDCl3, /ppm): 7.74-7.01 (m, 30H, Ph), 2.64-2.55 (m, 4H, -CH2-P-Pt-), 2.09-1.94

(m, 2H, -C-CH2-C-). 31P{1H}-NMR (121.5 MHz, CDCl3, /ppm): 4.87 (2J(PP) = 15.3 Hz,

1J(PtP) = 3349 Hz), 3.20 (2J(PP) = 15.3 Hz, 1J(PtP) = 3086 Hz). IR (KBr, (C�C)/cm-1):

147

2160 m (uncoordinated), 1719 m (coordinated). ESI-MS (m/z, assignment): 810.1 [M]+.

Single crystals of 24 for x-ray diffraction analysis were obtained by slow diffusion of n-

hexane into a concentrated CH2Cl2 solution of 24.

(Pt(dppp))2(PhC4Ph) (25): 0.11 g (0.14 mmol) of 24 and 0.086 g (0.14mmol) of

Pt(dppp)(CH2=CH2) were added into 15 ml of diethyl ether and stirred at room

temperature for 24 hours. The final light yellow suspension was then filtered and the

precipitate washed with a small amount of diethyl ether. The light yellow crude product

was recrystallized in THF/diethyl ether to form analytical pure product. Yield: 0.11 g

(55%). Anal. Calcd for C70H62P4Pt2: C, 59.3; H, 4.4. Found: C, 59.2; H, 4.4. 1H NMR

(300 MHz, C6D6, /ppm): 6.81-7.91 (m, 50H, Ph), 2.24 (m, 8H, -CH2-P-Pt-), 1.61-1.68

(m, 4H, -C-CH2-C-). 31P{1H}-NMR (121.5 MHz, C6D6, /ppm): 4.18 (2J(PP) = 26.7 Hz,

1J(PtP) = 3258 Hz), 3.94 (2J(PP) = 26.7 Hz, 1J(PtP) = 3267 Hz). IR (KBr, (C�C)/cm-1):

1758 m. ESI-MS (m/z, assignment): 1417.0 [M]+. Single crystals of 25 for x-ray

diffraction analysis were obtained by slow diffusion of diethyl ether vapor into a

concentrated THF solution of 25.

Pt(dppp)(CH3C4CH3) (26): 0.108 g (0.17 mmol) of Pt(dppp)(CH2=CH2) and 0.027g

(0.34 mmol) of 2, 4-hexadiyne were stirred in 10 ml of diethyl ether at room temperature

for 24 hours. The final light yellow suspension was then filtered and washed with a small

amount of diethyl ether. The light yellow crude product was recrystallized in THF/diethyl

ether to form analytical pure product. Yield: 0.08 g (70%). Anal. Calcd for C33H32P2Pt: C,

57.8; H, 4.7. Found: C, 57.5; H, 4.5. 1H NMR (300 MHz, C6D6, /ppm): 7.98-7.92, 7.71-

7.65 and 7.10-6.98 (m, 20H, Ph), 2.76 (doublet of triplets, 3H, CH3 on the coordinated

C�C, 3J(PtH) = 39.7 Hz, 4J(PH) = 7.6 Hz), 2.15 (m, 4H, -CH2-P-Pt-), 1.90 (doublet of

148

triplets, 3H, CH3 on the uncoordinated C�C, 5J(PtH) = 18.8 Hz, 6J(PH) = 3.5 Hz), 1.62

(m, 2H, -C-CH2-C-). 31P{1H}-NMR (121.5 MHz, C6D6, /ppm): 8,47 (2J(PP) = 31.1 Hz,

1J(PtP) = 3353 Hz), 7.29 (2J(PP) = 31.1 Hz, 1J(PtP) = 3124 Hz).. IR (KBr, (C�C)/cm-1):

2196 w (uncoordinated), 1749 s (coordinated). ESI-MS (m/z, assignment): 686.1 [M]+.

(Pt(dppp))2(CH3C4CH3) (27): the procedures were similar to those for preparing 25.

Yield: 40%. Anal. Calcd for C60H58P4Pt2: C, 55.7; H, 4.5. Found: C, 55.5; H, 4.5. 1H

NMR (300 MHz, C6D6, /ppm): 8.06-8.00, 7.86-7.80 and 7.10-6.93 (m, 40H, Ph), 2.51

(m, 6H, CH3), 2.26 (br, 8H, -CH2-P-Pt-), 1.74 (br, 4H, -C-CH2-C-). 31P{1H}-NMR (121.5

MHz, C6D6, /ppm): 8.54 (1J(PtP) = 3227 and 3258 Hz). IR (KBr, (C�C)/cm-1): 1705 w.

ESI-MS (m/z, assignment): 1293.0 [M]+.

149

Physical Measurements

150

Elemental Analyses

Elemental analyses of all the compounds prepared were carried out in the microanalysis

laboratory in the Department of Chemistry, the National University of Singapore.

NMR spectroscopy

1H- and 31P{1H}-NMR spectra were recorded at room temperature on a Bruker ACF 300

spectrometer.

Electron Spray Ionization mass spectroscopy (ESI-MS)

The ESI-MS spectra were measured on a Finnigan MAT 731 LCQ spectrometer.

Fast Atom Bombardment mass spectroscopy (FAB-MS)

The FAB-MS spectra were measured on a Finnigan Mat 95XL-T spectrometer.

Infrared spectroscopy

IR spectra (KBr) were recorded using a Bio-Rad Win-IR spectrophotometer.

UV-vis spectroscopy

UV-vis absorption spectra were recorded on a Shimadzu UV-1601PC UV-visible

spectrophotometer.

FL spectroscopy

Emission spectra in Chapter 2 and 4 were recorded on a Perkin-Elmer LS-50D

fluorescence spectrophotometer. Sample solutions used for room-temperature emission

measurements in Chapter 4 were degassed with at least three freeze-pump-thaw cycles.

Emission spectra in Chapter 7 were recorded on a SPEX-Fluorolog2 model F111A1

fluorescence spectrofluorometer. The lifetimes were measured using the Quanta Ray

DCR3 Nd:YAG laser with pulse-width of 8 ns and excitation wavelength of 355 nm.

151

Sample solutions for 77 K frozen glass emission spectra measurement in Chapter 7 were

prepared as follows:

1. Small amount of solid samples were added to ethanol solution.

2. The solutions were then dissolved using the ultra-sonic bath.

3. The solutions were filtered.

4. The filtrates were introduced into a quartz tube.

5. The quartz tubes were immersed in liquid nitrogen in a quartz optical Dewar flask for

measuring.

X-ray crystallography

The diffraction experiments were carried out on a Bruker AXS SMART CCD 3-circle

diffractometer at T = 223 K (except that: T = 295 K for crystal 22�THF), 2θ−ω scan with

a sealed tube at 23°C using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å).

The software used were: SMART123 for collecting frames of data, indexing reflection and

determination of lattice parameters; SAINT123 for integration of intensity of reflections

and scaling; SADABS124 for empirical absorption correction; and SHELXTL125 for space

group determination, structure solution and least-squares refinements on |F|2. The crystals

were mounted at the end of glass fibres and used for the diffraction experiments.

Anisotropic thermal parameters were refined for rest of the non-hydrogen atoms. The

hydrogen atoms were placed in their ideal positions.

Electrochemical measurements

A Bioanalytical Systems (BAS) model 100W electrochemical analyzer was used in all

electrochemical measurements. Tetra-n-butylammonium hexafluorophosphate (0.1 M)

was used as the supporting electrolyte unless otherwise stated. Cyclic voltammetry and

152

differential pulse voltammetry were performed in a conventional two-compartment

electrochemical cell. The platinum disk working electrode (area 0.02 cm2) electrode was

treated by polishing with 0.05 µm alumina on a microcloth and then sonicated for 5

minutes in deionized water followed by rinsing with the solvent used in the

electrochemical studies. An Ag/AgNO3 (0.1 M in CH3CN) electrode was used as

reference electrode. The half-wave potential (E1/2) values are the average of the cathodic

and anodic peak potentials for the oxidative and reductive waves of reversible couples.126

The potential of the Ag/AgNO3 reference electrode was calibrated against the

ferrocenium/ferrocene (Cp2Fe+/0) couple before and after each set of experiments to

ensure the accuracy of the potential measured127; the E1/2 of Cp2Fe+/0 was found to be

0.06±0.01 V vs. the Ag/AgNO3 reference.

153

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154

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175

Publications

1. Ronger Lin, John H. K. Yip, Ke Zhang, Kowk-Yin Wong, Kam Piu Ho Self-

Assembly and Molecular Recognition of a Luminescent Gold Rectangle

Journal of the American Chemical Society, 2004, 126, 15852-15869

2. Ke Zhang, J. Prabhavathy, John H. K. Yip, Lip Lin Koh, Geok Kheng Tan,

Jagadese J. Vittal First Examples of AuI-X-AgI Halonium Cations (X = Cl- and

Br-) Journal of the American Chemical Society, 2003, 125, 8452-8453

176

Appendices

177

1·CH2Cl2 2·2CH2Cl2

Empirical formula C39H30 Au2Cl4P2 C40H32Au2Br2Cl4P2

Formula weight 1096.30 1270.15

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Monoclinic

Space group P2(1)/c P2(1)/n

Unit cell dimensions a = 10.6602(6) Å α= 90° a = 14.1800(11) Å α= 90°

b = 18.8138(11) Å β= 103.6260(10)° b = 17.4938(14) Å β= 105.030(2)°

c = 19.3675(12) Å γ = 90° c = 17.4594(14) Å γ = 90°

Volume 3775.0(4) Å3 4182.9(6) Å3

Z 4 4

Density (calculated) 1.929 Mg/m3 2.017 Mg/m3

Absorption coefficient 8.159 mm-1 9.277 mm-1

F(000) 2080 2392

Crystal size 0.18 x 0.14 x 0.10 mm3 0.30 x 0.28 x 0.07 mm3

Theta range for data collection 1.53 to 27.50° 1.68 to 27.50°

Index ranges -7�h�13, -24�k�24, -25�l�22 -18�h�18, -22�k�22, -22�l�22

Reflections collected 26799 54207

Independent reflections 8670 [R(int) = 0.0526] 9605 [R(int) = 0.0666]

Completeness to theta = X 100.0 % (X = 27.50°) 100.0 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.4959 and 0.3214 0.5628 and 0.1673

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 8670 / 0 / 424 9605 / 42 / 459

Goodness-of-fit on F2 b 1.053 1.055

Final R indices [I>2sigma(I)] c R1 = 0.0436, wR2 = 0.0930 R1 = 0.0455, wR2 = 0.1024 R indices (all data) R1 = 0.0640, wR2 = 0.1054 R1 = 0.0643, wR2 = 0.1104 Largest diff. peak and hole 1.725 and -0.814 e.Å-3 1.924 and -1.135 e.Å-3

A-1. Crystal data and structure refinement for 1·CH2Cl2 and 2·2CH2Cl2 a

a For crystal data and structure refinement of 1·0.5Et2O and 2·Et2O, please refer to reference 18b.

For all crystal structure refinement: b GOF = [(w(Fo2-Fc2)2/(n-p)]1/2

c R1= Σ(||Fo|-|Fc||)/ Σ(|Fo|); wR2 = {Σ[w(Fo2-Fc2)]/ Σ[w(Fo2)2]}1/2

178

3·CH2Cl2 4·Et2O

Empirical formula C39H30Au2Cl2I2P2 C40H33Au2N2O6.50P2

Formula weight 1279.20 1101.56

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Orthorhombic Orthorhombic

Space group Pbcn Pccn

Unit cell dimensions a = 21.2783(15) Å α= 90° a = 21.247(3) Å α= 90°

b = 19.4890(14) Å β= 90° b = 18.090(2) Å β= 90°

c = 18.5466(12) Å γ = 90° c = 20.065(2) Å γ = 90°

Volume 7691.1(9) Å3 7712.4(16) Å3

Z 8 8

Density (calculated) 2.209 Mg/m3 1.897 Mg/m3

Absorption coefficient 9.476 mm-1 7.733 mm-1

F(000) 4736 4216

Crystal size 0.38 x 0.30 x 0.28 mm3 0.36 x 0.36 x 0.26 mm3

Theta range for data collection 1.42 to 25.00° 1.48 to 27.50°

Index ranges -22�h�25, -23�k�23, -22�l�16 -27�h�27, -23�k�23, -26�l�26

Reflections collected 40691 97103

Independent reflections 6772 [R(int) = 0.0912] 8863 [R(int) = 0.0590]

Completeness to theta = X 100.0 % (X = 25.00°) 100.0 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.1767 and 0.1233 0.2384 and 0.1673

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 6772 / 3 / 433 8863 / 6 / 502

Goodness-of-fit on F2 1.079 1.055

Final R indices [I>2sigma(I)] R1 = 0.0483, wR2 = 0.1012 R1 = 0.0530, wR2 = 0.1215

R indices (all data) R1 = 0.0651, wR2 = 0.1071 R1 = 0.0753, wR2 = 0.1323

Largest diff. peak and hole 1.646 and -2.959 e.Å-3 5.998 and -4.467 e.Å-3

A-2. Crystal data and structure refinement for 3·CH2Cl2 and 4·0.5Et2O

179

5·THF 6·0.75 CH2Cl2

Empirical formula C58H46Au2OP2 C70.75H47.50Cl1.50P2Au2

Formula weight 1214.82 1406.64

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Monoclinic

Space group P2(1)/c P2(1)/n

Unit cell dimensions a = 14.7039(6) Å α= 90° a = 18.089(3) Å α= 90°

b = 16.7204(7) Å β= 102.2360(10)° b = 23.690(4) Å β= 106.448(5)°

c = 21.3151(9) Å γ = 90° c = 27.079(5) Å γ = 90°

Volume 5121.4(4) Å3 11129(4) Å3

Z 4 8

Density (calculated) 1.576 Mg/m3 1.679 Mg/m3

Absorption coefficient 5.823 mm-1 5.440 mm-1

F(000) 2360 5484

Crystal size 0.40 x 0.16 x 0.04 mm3 0.50 x 0.24 x 0.18 mm3

Theta range for data collection 1.56 to 25.00° 1.45 to 27.50°

Index ranges -17�h�17, -19�k�15, -25�l�25 -23�h�23, -30�k�30, -35�l�31

Reflections collected 29072 77952

Independent reflections 8992 [R(int) = 0.0479] 25524 [R(int) = 0.0727]

Completeness to theta = X 99.6 % (X = 25.00°) 99.8 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.8005 and 0.2042 0.4409 and 0.1718

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 8992 / 16 / 563 25524 / 4 / 1378

Goodness-of-fit on F2 1.008 1.053

Final R indices [I>2sigma(I)] R1 = 0.0375, wR2 = 0.0933 R1 = 0.0688, wR2 = 0.1747

R indices (all data) R1 = 0.0561, wR2 = 0.1003 R1 = 0.1204, wR2 = 0.1959

Largest diff. peak and hole 1.417 and -0.516 e.Å-3 5.391 and -2.027 e.Å-3

A-3. Crystal data and structure refinement for 5·THF and 6·0.75 CH2Cl2

180

7·2CH2Cl2 8·2CH2Cl2

Empirical formula C78H60AgAu4Cl8F6P4Sb C78H60AgAu4Br4Cl4F6P4Sb

Formula weight 2536.23 2714.07

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Tetragonal Tetragonal

Space group I4/m I4/m

Unit cell dimensions a = 17.952(3) Å α= 90° a = 18.0180(5) Å α= 90°

b = 17.952(3) Å β= 90° b = 18.0180(5) Å β= 90°

c = 25.388 Å γ = 90° c = 25.7020(13) Å γ = 90°

Volume 8182.0(18) Å3 8344.1(5) Å3

Z 4 4

Density (calculated) 2.059 Mg/m3 2.160 Mg/m3

Absorption coefficient 8.100 mm-1 9.730 mm-1

F(000) 4768 5056

Crystal size 0.26 x 0.24 x 0.12 mm3 0.24 x 0.20 x 0.10 mm3

Theta range for data collection 1.60 to 24.95° 1.60 to 25.00°

Index ranges -21�h�19, -21�k�18, -30�l�29 -20�h�21, -18�k�21, -30�l�30

Reflections collected 23539 24204

Independent reflections 3693 [R(int) = 0.0577] 3773 [R(int) = 0.0796]

Completeness to theta = X 99.9 % (X = 24.95°) 99.8 % (X = 25.00°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.4432 and 0.2272 0.4429 and 0.2036

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 3693 / 22 / 246 3773 / 0 / 251

Goodness-of-fit on F2 1.056 1.020

Final R indices [I>2sigma(I)] R1 = 0.0454, wR2 = 0.1213 R1 = 0.0540, wR2 = 0.1356

R indices (all data) R1 = 0.0647, wR2 = 0.1318 R1 = 0.0943, wR2 = 0.1536

Largest diff. peak and hole 2.505 and -0.912 e.Å-3 2.685 and -0.708 e.Å-3

A-4. Crystal data and structure refinement for 7·2CH2Cl2 and 8·2CH2Cl2

181

9·3CH3CN·Et2O·0.5H2O 10·4.6CH3CN

Empirical formula C124H109Cu4F12N3O1.50P10S2 C119.20H109.80Ag4Cl2N4.60O8P8S2

Formula weight 2521.12 2549.11

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Monoclinic

Space group P2(1)/n P2(1)/n

Unit cell dimensions a = 14.0959(6) Å α= 90° a = 13.4521(18) Å α= 90°

b = 30.9985(13) Å β= 90.4330(10)° b = 20.981(3) Å β= 108.17°

c = 15.1624(6) Å γ = 90° c = 21.568(3) Å γ = 90°

Volume 6625.0(5) Å3 5783.9(13) Å3

Z 2 2

Density (calculated) 1.264 Mg/m3 1.489 Mg/m3

Absorption coefficient 0.848 mm-1 0.919 mm-1

F(000) 2584 2635

Crystal size 0.50 x 0.30 x 0.30 mm3 0.14 x 0.14 x 0.12 mm3

Theta range for data collection 1.50 to 25.00° 1.87 to 25.00°

Index ranges -16�h�16, -36�k�27, -18�l�18 -15�h�15, -24�k�20, -25�l�25

Reflections collected 38247 31874

Independent reflections 11660 [R(int) = 0.0347] 10157 [R(int) = 0.0667]

Completeness to theta = X 100.0 % (X = 25.00°) 99.8 % (X = 25.00°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.7849 and 0.6764 0.8977 and 0.8821

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 11660 / 360 / 782 10157 / 72 / 679

Goodness-of-fit on F2 1.064 1.074

Final R indices [I>2sigma(I)] R1 = 0.0567, wR2 = 0.1782 R1 = 0.0619, wR2 = 0.1511

R indices (all data) R1 = 0.0743, wR2 = 0.1909 R1 = 0.0878, wR2 = 0.1642

Largest diff. peak and hole 0.961 and -0.263 e.Å-3 1.495 and -0.980 e.Å-3

A-5. Crystal data and structure refinement for 9·3CH3CN·Et2O·0.5H2O and 10·4.6CH3CN

182

11·0.5CH2Cl2 12

Empirical formula C64.50H47Au2ClP2S4 C74 H62 Fe2 P4 Pt

Formula weight 1441.58 1381.91

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Triclinic Monoclinic

Space group P-1 P2(1)/c

Unit cell dimensions a = 10.9764(4) Å α = 92.7140(10)° a = 17.5409(8) Å α = 90°

b = 11.5449(5) Å β = 93.1180(10)° b = 18.4087(8) Å β = 112.0530(10)°

c = 23.3485(9) Å γ = 111.3410(10)° c = 20.4010(9) Å γ = 90°

Volume 2744.61(19) Å3 6105.6(5) Å3

Z 2 4

Density (calculated) 1.744 Mg/m3 1.503 Mg/m3

Absorption coefficient 5.640 mm-1 2.903 mm-1

F(000) 1406 2784

Crystal size 0.24 x 0.14 x 0.09 mm3 0.34 x 0.30 x 0.22 mm3

Theta range for data collection 0.88 to 25.00° 1.25 to 27.50°

Index ranges -13�h�13, -13�k�13, -27�l�27 -22�h�22, -19�k�23, -23�l�26

Reflections collected 29307 42864

Independent reflections 9616 [R(int) = 0.0536] 14022 [R(int) = 0.0406]

Completeness to theta = X 99.5 % (X = 25.00°) 99.9 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.6308 and 0.3447 0.5676 and 0.4386

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 9616 / 0 / 671 14022 / 0 / 733

Goodness-of-fit on F2 1.055 1.006

Final R indices [I>2sigma(I)] R1 = 0.0635, wR2 = 0.1520 R1 = 0.0352, wR2 = 0.0795

R indices (all data) R1 = 0.1023, wR2 = 0.1710 R1 = 0.0646, wR2 = 0.0929

Largest diff. peak and hole 3.136 and -2.298 e.Å-3 1.169 and -0.567 e.Å-3

A-6. Crystal data and structure refinement for 11·0.5CH2Cl2 and 12

183

14·0.5Et2O 15·1.5CH2Cl2

Empirical formula C76 H67 Ag Fe2 N O3.50 P4 Pt C75.50 H65 Cl3 Cu F6 Fe2 P5 Pt

Formula weight 1588.85 1717.80

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Triclinic

Space group P2(1)/n P-1

Unit cell dimensions a = 13.9839(6) Å α= 90° a = 10.5974(14) Å α = 80.707(3)°

b = 27.9967(12) Å β= 99.7130(10)° b = 15.267(2) Å β= 88.729(3)°

c = 17.2745(7) Å γ = 90° c = 23.932(3) Å γ = 70.531(3)°

Volume 6666.1(5) Å3 3600.6(8) Å3

Z 4 2

Density (calculated) 1.583 Mg/m3 1.584 Mg/m3

Absorption coefficient 2.954 mm-1 2.903 mm-1

F(000) 3180 1714

Crystal size 0.60 x 0.20 x 0.14 mm3 0.20 x 0.14 x 0.14 mm3

Theta range for data collection 1.40 to 27.50° 1.55 to 27.50°

Index ranges -18�h�17, -36�k�34, -21�l�22 -13�h�13, -19�k�19, -31�l�31

Reflections collected 46731 46659

Independent reflections 15317 [R(int) = 0.0428] 16489 [R(int) = 0.0468]

Completeness to theta = X 100.0 % (X = 27.50°) 99.8 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.6825 and 0.2702 0.6867 and 0.5944

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 15317 / 6 / 793 16489 / 6 / 865

Goodness-of-fit on F2 1.033 1.028

Final R indices [I>2sigma(I)] R1 = 0.0406, wR2 = 0.0932 R1 = 0.0470, wR2 = 0.1159

R indices (all data) R1 = 0.0563, wR2 = 0.0996 R1 = 0.0657, wR2 = 0.1209

Largest diff. peak and hole 2.411 and -0.478 e.Å-3 1.877 and -1.562 e.Å-3

A-7. Crystal data and structure refinement for 14·0.5Et2O and 15·1.5CH2Cl2

184

16·1.5CH2Cl2 17·0.75CH2Cl2

Empirical formula C75.50 H65 Cl5 Fe2 Hg P4 Pt C75.75 H63.50 Cl1.50 F6 Fe2 O P5 Pt Rh

Formula weight 1780.78 1721.49

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Monoclinic

Space group P2(1)/n P2(1)/n

Unit cell dimensions a = 16.1048(11) Å α= 90° a = 12.3820(12) Å α= 90°

b = 16.1486(10) Å β= 92.835(2)° b = 26.421(3) Å β= 91.077(3)°

c = 27.2878(19) Å γ = 90° c = 22.792(2) Å γ = 90°

Volume 7088.1(8) Å3 7455.1(13) Å3

Z 4 4

Density (calculated) 1.669 Mg/m3 1.534 Mg/m3

Absorption coefficient 4.849 mm-1 2.687 mm-1

F(000) 3492 3422

Crystal size 0.24 x 0.14 x 0.10 mm3 0.30 x 0.24 x 0.16 mm3

Theta range for data collection 1.44 to 25.00° 1.54 to 25.00°

Index ranges -19�h�18, -19�k�10, -32�l�32 -14�h�14, -30�k�31, -18�l�27

Reflections collected 40456 43028

Independent reflections 12470 [R(int) = 0.0741] 13133 [R(int) = 0.0633]

Completeness to theta = X 99.9 % (X = 25.00°) 100.0 % (X = 25.00°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.6427 and 0.3891 0.6730 and 0.4994

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 12470 / 4 / 811 13133 / 93 / 853

Goodness-of-fit on F2 1.159 1.056

Final R indices [I>2sigma(I)] R1 = 0.0737, wR2 = 0.1573 R1 = 0.0859, wR2 = 0.2378

R indices (all data) R1 = 0.1037, wR2 = 0.1679 R1 = 0.1163, wR2 = 0.2551

Largest diff. peak and hole 2.961 and -1.741 e.Å-3 3.151 and -1.669 e.Å-3

A-8. Crystal data and structure refinement for 16·1.5CH2Cl2 and 17·0.75CH2Cl2

185

18·toluene·n-hexane 19·1.9THF

Empirical formula C90 H84 Fe2 O3 P4 Pt W C84.60 H77.20 Fe2 Mo O4.90 P4 Pt

Formula weight 1828.09 1698.87

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Monoclinic Monoclinic

Space group P2(1)/c P2(1)/c

Unit cell dimensions a = 16.5486(9) Å α= 90° a = 16.5134(9) Å α= 90°

b = 16.0278(8) Å β= 92.3790(10)° b = 16.0323(9) Å β= 91.5760(10)°

c = 29.4537(16) Å γ = 90° c = 29.3555(17) Å γ = 90°

Volume 7805.5(7) Å3 7768.9(8) Å3

Z 4 4

Density (calculated) 1.556 Mg/m3 1.452 Mg/m3

Absorption coefficient 3.751 mm-1 2.451 mm-1

F(000) 3648 3424

Crystal size 0.70 x 0.60 x 0.20 mm3 0.20 x 0.20 x 0.16 mm3

Theta range for data collection 1.77 to 27.50° 1.45 to 25.00°

Index ranges -21�h�16, -20�k�20, -37�l�38 -19�h�19, -19�k�19, -34�l�34

Reflections collected 54123 82375

Independent reflections 17912 [R(int) = 0.0353] 13675 [R(int) = 0.0633]

Completeness to theta = X 99.9 % (X = 27.50°) 100.0 % (X = 25.00°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.5208 and 0.1788 0.6952 and 0.6399

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 17912 / 13 / 857 13675 / 15 / 903

Goodness-of-fit on F2 1.062 1.064

Final R indices [I>2sigma(I)] R1 = 0.0340, wR2 = 0.0847 R1 = 0.0439, wR2 = 0.1105

R indices (all data) R1 = 0.0427, wR2 = 0.0886 R1 = 0.0562, wR2 = 0.1160

Largest diff. peak and hole 1.418 and -0.662 e.Å-3 1.658 and -1.009 e.Å-3

A-9. Crystal data and structure refinement for 18·toluene·n-hexane and 19·1.9THF

186

20 22·THF

Empirical formula C50 H44 Fe2 P2 Pt C45 H44 O P2 Pt

Formula weight 1013.58 857.83

Temperature 223(2) K 295(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Triclinic Orthorhombic

Space group P-1 Pnma

Unit cell dimensions a = 6.2495(3) Å α= 70.1670(10)° a = 30.0064(15) Å α= 90°

b = 11.9919(5) Å β= 86.2080(10)° b = 23.4345(12) Å β= 90°

c = 14.6317(6) Å γ = 79.6390(10)° c = 10.7582(5) Å γ = 90°

Volume 1014.67(8) Å3 7565.0(6) Å3

Z 1 8

Density (calculated) 1.659 Mg/m3 1.506 Mg/m3

Absorption coefficient 4.258 mm-1 3.828 mm-1

F(000) 504 3440

Crystal size 0.32 x 0.22 x 0.20 mm3 0.38 x 0.26 x 0.20 mm3

Theta range for data collection 1.83 to 27.50° 1.61 to 27.50°

Index ranges -8�h�8, -15�k�15, -18�l�18 -38�h�36, -30�k�30, -12�l�13

Reflections collected 13360 51463

Independent reflections 4657 [R(int) = 0.0210] 8897 [R(int) = 0.0408]

Completeness to theta = X 99.9 % (X = 27.50°) 100.0 % (X = 27.50°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.4831 and 0.3428 0.5148 and 0.3241

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 4657 / 0 / 251 8897 / 17 / 459

Goodness-of-fit on F2 1.051 1.021

Final R indices [I>2sigma(I)] R1 = 0.0158, wR2 = 0.0401 R1 = 0.0318, wR2 = 0.0664

R indices (all data) R1 = 0.0158, wR2 = 0.0401 R1 = 0.0461, wR2 = 0.0707

Largest diff. peak and hole 0.996 and -0.404 e.Å-3 1.222 and -1.152 e.Å-3

A-10. Crystal data and structure refinement for 20 and 22·THF

187

24 25

Empirical formula C43 H36 P2 Pt C70 H62 P4 Pt2

Formula weight 809.75 1417.26

Temperature 223(2) K 223(2) K

Wavelength 0.71073 Å 0.71073 Å

Crystal system Triclinic Monoclinic

Space group P-1 P2(1)/n

Unit cell dimensions a = 10.7412(5) Å α= 83.3900(10)° a = 10.8152(7) Å α= 90°

b = 12.6475(6) Å β= 88.0370(10)° b = 20.0454(12) Å β= 92.4740(10)°

c = 13.7503(6) Å γ = 66.3590(10)° c = 26.8225(17) Å γ = 90°

Volume 1699.68(14) Å3 5809.6(6) Å3

Z 2 4

Density (calculated) 1.582 Mg/m3 1.620 Mg/m3

Absorption coefficient 4.252 mm-1 4.963 mm-1

F(000) 804 2792

Crystal size 0.40 x 0.10 x 0.08 mm3 0.50 x 0.20 x 0.20 mm3

Theta range for data collection 1.77 to 25.00° 1.52 to 30.01°

Index ranges -12�h�12, -15�k�15, -16�l�16 -14�h�15, -28�k�26, -20�l�37

Reflections collected 18338 46864

Independent reflections 5990 [R(int) = 0.0271] 16579 [R(int) = 0.0317]

Completeness to theta = X 100.0 % (X = 25.00°) 97.9 % (X = 30.01°)

Absorption correction Sadabs, (Sheldrick 2001) Sadabs, (Sheldrick 2001)

Max. and min. transmission 0.7272 and 0.2811 0.4368 and 0.1904

Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 5990 / 0 / 556 16579 / 0 / 685

Goodness-of-fit on F2 1.080 1.025

Final R indices [I>2sigma(I)] R1 = 0.0276, wR2 = 0.0695 R1 = 0.0325, wR2 = 0.0752

R indices (all data) R1 = 0.0287, wR2 = 0.0702 R1 = 0.0440, wR2 = 0.0792

Largest diff. peak and hole 3.840 and -0.667 e.Å-3 2.971 and -0.682 e.Å-3

A-11. Crystal data and structure refinement for 24 and 25

188

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A-12. UV-visible absorption spectrum of complex 1 in CH2Cl2 at room temperature

300 400 500 600 7000

20000

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Wavelength (nm)

A-13. UV-visible absorption spectrum of complex 2 in CH2Cl2 at room temperature

189

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A-14. UV-visible absorption spectrum of complex 3 in CH2Cl2 at room temperature

A-15. UV-visible absorption spectrum of complex 5 in CH2Cl2 at room temperature

300 400 500 600 7000

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Ext

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Wavelength (nm)

190

400 450 500 550 6000

100

200

300

400

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700

Inte

nsity

(a.u

.)

Wavelength (nm)

A-16. Emission spectrum of complex 1 in CH2Cl2 at room temperature (excited at 390 nm)

400 500 6000

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nsity

(a.u

.)

Wavelength (nm)

A-17. Emission spectrum of complex 2 in CH2Cl2 at room temperature (excited at 390 nm)

191

400 500 6000

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nsity

(a.u

.)

Wavelength (nm)

A-18. Emission spectrum of complex 4 in CH2Cl2 at room temperature (excited at 390 nm)

400 450 500 550 6000

100

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nsity

(a.u

.)

Wavelength (nm)

A-19. Emission spectrum of complex 5 in CH2Cl2 at room temperature (excited at 390 nm)

192

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nsity

(a.

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Wavelength (nm)

A-20. Emission spectrum of complex 2 in solid state at room temperature (excited at 300 nm)

A-21. Emission spectrum of complex 4 in solid state at room temperature (excited at 350 nm)

500 600 700 8000

100

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700

Intn

esity

(a.u

.)

Wavelength (nm)

193

AuI #132-142 RT: 4.47-4.79 AV: 11 NL: 2.02E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

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65

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Rel

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ance

1936.5

1937.4

811.21067.2 1612.8

1390.7744.1705.0 921.9 1628.81164.6 1939.4623.5 1289.2 1846.1898.7 944.7 1392.3 1713.51588.7 1993.0477.4297.3 414.7201.9160.0

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100

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Inte

nsity

(a.u

.)

Wavelength (nm)

A-22. Emission spectrum of complex 5 in solid state at room temperature (excited at 410 nm)

A-23. ESI-MS spectrum of complex 3

194

AuNO3 #5-13 RT: 0.12-0.35 AV: 9 NL: 1.12E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

743.5

744.2

1754.7

1753.6

1621.2

860.4 1164.4 1756.61490.7 1624.11171.0 1844.4978.3 1612.3686.2 1295.9 1446.81107.1842.1 1958.1656.1501.7183.4 362.1232.7159.9

AU-CCPH1 #224-246 RT: 5.59-6.15 AV: 23 NL: 5.31E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1339.1

1619.0

1620.0

1883.71340.1

1720.9

1721.91423.1 1941.5

1636.91586.8

1519.4743.5

1289.3744.4

1022.7 1074.1805.5 1959.1893.0 1247.1674.7 1142.2977.2541.9388.7328.3191.3149.0

A-24. ESI-MS spectrum of complex 4

A-25. ESI-MS spectrum of complex 5

195

AU-CCAN1 #141-170 RT: 3.17-3.90 AV: 30 NL: 1.86E7T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100R

elat

ive

Abu

ndan

ce743.5

1539.1

1540.1

942.4

744.3 1920.8

1141.3

1686.8 1936.91173.0 1918.51718.91523.1

1904.81174.0 1571.01289.3 1938.91888.8

1507.01305.2 1573.01042.5 1789.8437.9 751.5542.9 1176.1892.3377.2 673.8183.2 283.6145.9

A-26. ESI-MS spectrum of complex 6

A-27. FAB-MS spectrum of complex 7

196

A-28. FAB-MS spectrum of complex 8

A-29. ESI-MS spectrum of ligand H2SAnS

197

Pt-Fc #36-81 RT: 0.95-2.22 AV: 46 NL: 6.81E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100R

elat

ive

Abu

ndan

ce1381.0

1414.91379.01488.8

1173.1

593.11490.9

1171.1

1577.9

1174.0

1188.1

1343.0

1190.11580.9

595.2 1337.0691.01104.9789.0 1061.8 1204.1199.1 591.2 959.2 1607.6748.1 1786.8411.2 1991.4458.5200.9 1907.7343.3183.5

PT-AU-CLO4' #123-130 RT: 3.66-3.83 AV: 8 NL: 1.19E8T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1578.0

1579.0

1580.9

1576.1

1582.91161.0 1574.21369.0 1602.9565.6 1842.81235.31084.8898.5 1732.7647.4 776.9 1907.7998.0

A-30. ESI-MS spectrum of complex 12

A-31. ESI-MS spectrum of complex 13

198

Pt-Ag-NO3 #1 RT: 0.01 AV: 1 NL: 1.87E8T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1488.9

1487.81490.8

1492.8

1106.2 1723.31484.8 1568.11358.51056.7

Pt-Cu-PF6 #1 RT: 0.00 AV: 1 NL: 7.95E8T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1445.0

1445.9

1443.0

1447.9

1061.11441.0 1449.81063.1

1464.01439.21057.9 1578.8 1838.51224.3848.4 1643.01153.4

A-32. ESI-MS spectrum of complex 14

A-33. ESI-MS spectrum of complex 15

199

Pt-Hg-Cl2 #269 RT: 7.92 AV: 1 NL: 1.82E8T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1172.1

1171.0

1174.1

1176.2 1618.71177.7

1443.7 1620.51248.8 1407.0 1493.01169.0795.8 1061.1740.5592.9270.4

Pt-Rh-PF6 #12-55 RT: 0.37-1.32 AV: 21 NL: 1.01E7T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1511.9

1510.9

1513.9

1444.9

1515.91442.9

1578.9

1060.9 1344.91273.9538.4 1580.9916.1584.7 1173.7797.2741.4494.6 1723.9 1777.8354.0279.0216.6 1871.6145.2

A-34. ESI-MS spectrum of complex 16

A-35. ESI-MS spectrum of complex 17

200

Pt-W #62-65 RT: 2.11-2.20 AV: 4 NL: 7.22E5T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1648.2

1650.11647.2

1645.4

1187.8

1190.4 1643.21099.4 1653.71619.5 1699.1

1399.11199.1 1461.9924.0593.4 1383.0 1831.71600.81077.9 1894.1829.1793.9611.9545.9130.4 280.3 491.6

Pt-Fc-Me #51 RT: 1.35 AV: 1 NL: 4.69E7T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1013.0

1014.0

1016.0

1010.9810.2736.4594.1691.3 816.1 1003.0 1460.0589.4465.0 1048.8 1409.0 1962.51213.0418.2 1566.4 1618.2 1829.1309.2181.0

A-36. ESI-MS spectrum of complex 18

A-37. ESI-MS spectrum of complex 20

201

(ptpph3)(PhC2Ph) #115-140 RT: 2.73-3.43 AV: 26 NL: 6.54E5T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

719.1

721.1

718.2

897.9

896.9

760.1

786.1 899.9 1369.8473.8 977.0 1693.5540.7 1253.91032.1 1781.0852.8641.1 1429.7 1629.3472.5 1514.7 1931.61033.0 1145.4 1875.1263.3 396.8183.3147.8

(ptdp)(PhC2Ph) #33-44 RT: 0.64-0.97 AV: 12 NL: 1.30E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

786.1

787.1

1390.0

867.1

1406.9

920.6624.4 742.2

1705.8720.1622.3

922.5 1026.5 1409.0 1704.71547.8626.8 1841.8606.2 1998.51214.8 1375.8 1450.11070.3 1661.4506.2272.3183.3 374.3

A-38. ESI-MS spectrum of complex 21

A-39. ESI-MS spectrum of complex 22

202

(ptpph3)(PhC4Ph) #162-185 RT: 4.78-5.51 AV: 24 NL: 3.83E5T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

922.0

921.0

924.0

721.2

719.2

1667.31841.61102.4 1542.0717.2 1445.41101.4840.2

1443.4 1639.3 1839.91104.5 1323.1 1844.6660.2 755.0476.7 1717.7950.9 1979.5999.5540.0 1193.3262.0183.3 397.0152.0

(ptdp)(PhC4Ph) #114-127 RT: 2.86-3.25 AV: 14 NL: 1.46E6T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

810.1

1414.0

1415.0

812.1

623.5 1430.0

814.01431.9

830.2641.1 889.1766.1 1213.3 1446.4 1542.0 1753.6967.7 1406.8607.3 1937.51112.0532.5450.1335.4183.5

A-40. ESI-MS spectrum of complex 23

A-41. ESI-MS spectrum of complex 24

203

(ptdp)2(PhC4Ph) #74-82 RT: 1.98-2.19 AV: 9 NL: 4.08E7T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1417.0

1416.01418.9

1213.1

1212.2

1215.2

1449.1

1452.01414.21217.2

1560.51339.3719.7 1209.2869.8623.8 1028.6 1618.5 1765.7 1960.01908.7190.8 511.6440.6

(ptdp)(CH3C4CH3) #9-15 RT: 0.22-0.38 AV: 6 NL: 9.85E5T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

686.1

687.1

689.1623.7

1291.0622.2

1292.9 1506.0704.1 1212.2606.1 1363.4765.4 1507.6 1724.8527.2 1964.5464.6 1211.3834.3 908.1 1828.7395.9 1062.7165.1 301.1

A-42. ESI-MS spectrum of complex 25

A-43. ESI-MS spectrum of complex 26

204

(ptdp)2(CH3C4CH3) #113 RT: 2.94 AV: 1 NL: 2.11E7T: + c Full ms [ 50.00-2000.00]

200 400 600 800 1000 1200 1400 1600 1800 2000m/z

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

Rel

ativ

e A

bund

ance

1293.0

1294.9

1213.4

1297.11211.6

1373.01135.1 1456.3 1559.8845.5 1647.7652.0 1968.7760.6563.7 1742.3985.4 1133.9

4.0

00

0

20

.13

4

4.2

88

0

Inte

gra

l

8.2

60

78

.25

00

8.2

43

38

.23

80

8.2

27

3

7.7

09

57

.70

55

7.6

82

87

.67

74

7.6

64

07

.66

00

7.6

37

37

.63

19

7.5

47

67

.54

23

7.5

30

27

.52

36

7.5

11

57

.50

62

7.4

99

57

.49

41

7.4

87

47

.47

81

7.4

68

77

.46

20

7.4

54

07

.44

60

7.4

39

37

.43

39

7.4

31

27

.42

46

7.1

36

97

.12

62

7.1

14

27

.10

35

(ppm)

6.706.806.907.007.107.207.307.407.507.607.707.807.908.008.108.208.308.408.50

A-44. ESI-MS spectrum of complex 27

A-45. 1H-NMR spectrum of complex 3 in CDCl3 at room temperature

205

4.0

00

0

21

.01

0

4.1

47

2

Inte

gra

l

8.2

75

08

.26

70

8.2

64

38

.25

76

8.2

52

28

.24

42

8.2

41

5

7.7

02

47

.69

83

7.6

93

07

.68

23

7.6

75

67

.67

03

7.6

55

57

.65

15

7.6

46

27

.62

88

7.6

23

47

.58

86

7.5

80

67

.57

39

7.5

64

67

.55

65

7.5

44

57

.54

05

7.5

32

47

.52

71

7.5

15

17

.51

24

7.5

05

77

.50

30

7.4

97

77

.49

36

7.4

88

37

.48

29

7.4

77

67

.47

09

7.4

64

27

.46

02

7.4

54

87

.20

20

7.1

91

37

.18

06

7.1

68

57

.15

78

7.1

48

5

(ppm)

6.806.907.007.107.207.307.407.507.607.707.807.908.008.108.208.308.408.508.60

32

.87

40

(ppm)

15161718192021222324252627282930313233343536373839404142434445464748495051

A-46. 31P{1H}-NMR spectrum of complex 3 in CDCl3 at room temperature

A-47. 1H-NMR spectrum of complex 4 in CD2Cl2 at room temperature

206

20

.31

09

(ppm)

-34-30-26-22-18-14-10-6-2261014182226303438424650545862667074

4.0

00

0

21

.66

9

4.9

28

5

3.9

92

3

Inte

gra

l

8.3

00

98

.29

15

8.2

78

18

.26

88

7.6

98

87

.67

74

7.6

72

17

.65

60

7.6

34

6

7.5

16

97

.50

22

7.4

96

87

.48

07

7.4

74

17

.46

34

7.4

54

07

.44

86

7.4

39

37

.42

59

7.4

17

97

.40

98

7.2

27

97

.22

25

7.2

17

27

.20

65

7.2

02

57

.19

44

7.1

81

17

.13

42

7.1

23

57

.11

15

7.1

00

8

(ppm)

6.806.907.007.107.207.307.407.507.607.707.807.908.008.108.208.308.408.508.60

A-48. 31P{1H}-NMR spectrum of complex 4 in CD2Cl2 at room temperature

A-49. 1H-NMR spectrum of complex 5 in CDCl3 at room temperature

207

36

.51

62

(ppm)

-226101418222630343842465054586266707478

3.9

71

2

3.9

50

7

2.0

00

0

3.9

61

2

8.3

66

5

21

.26

5

4.0

03

0

Inte

gra

l

8.8

33

48

.80

66

8.4

15

98

.39

19

8.2

90

2

7.9

63

77

.93

43

7.8

08

57

.78

44

7.7

67

17

.74

43

7.5

12

97

.49

55

7.4

91

47

.46

34

7.4

37

97

.43

39

7.4

15

27

.41

12

7.2

13

27

.20

11

7.1

89

17

.17

84

(ppm)

7.007.107.207.307.407.507.607.707.807.908.008.108.208.308.408.508.608.708.808.909.009.10

A-50. 31P{1H}-NMR spectrum of complex 5 in CDCl3 at room temperature

A-51. 1H-NMR spectrum of complex 6 in CDCl3 at room temperature

208

36

.76

73

(ppm)

-8-4048121620242832364044485256606468727680

4.0

00

0

20

.71

0

4.1

73

6

Inte

gra

l

8.1

21

28

.11

18

8.0

98

48

.08

91

7.8

14

87

.79

34

7.7

88

07

.76

93

7.7

47

9

7.5

90

0

7.5

70

0

7.5

45

97

.53

78

7.5

16

4

7.2

38

27

.22

75

7.2

14

17

.20

47

(ppm)

7.007.057.107.157.207.257.307.357.407.457.507.557.607.657.707.757.807.857.907.958.008.058.108.158.208.258.308.358.40

A-52. 31P{1H}-NMR spectrum of complex 6 in CDCl3 at room temperature

A-53. 1H-NMR spectrum of complex 7 in DMSO-d6 at room temperature

209

26

.84

63

(ppm)

-12-8-40481216202428323640444852566064

4.0

00

0

20

.70

7

4.0

27

2

Inte

gra

l

8.1

34

5

7.8

18

8

7.7

93

47

.77

33

7.7

50

6

7.5

79

3

7.5

55

2

7.2

42

2

(ppm)

6.907.007.107.207.307.407.507.607.707.807.908.008.108.208.308.408.50

A-54. 31P{1H}-NMR spectrum of complex 7 in DMSO-d6 at room temperature

A-55. 1H-NMR spectrum of complex 8 in DMSO-d6 at room temperature

210

28

.91

92

(ppm)

-30-26-22-18-14-10-6-226101418222630343842465054586266707478

A-56. 31P{1H}-NMR spectrum of complex 8 in DMSO-d6 at room temperature

A-57. 1H-NMR spectrum of ligand H2SAnS in CD2Cl2 at room temperature

211

4.0

00

0

81

.81

2

4.2

97

7

7.0

08

0

Inte

gra

l

8.7

07

18

.69

64

8.6

84

48

.67

37

7.2

80

9

7.1

37

8

6.3

84

56

.37

38

6.3

61

86

.35

11

3.0

82

6

(ppm)

2.42.83.23.64.04.44.85.25.66.06.46.87.27.68.08.48.89.29.6

A-58. 1H-NMR spectrum of complex 9 in CD2Cl2 at room temperature

A-59. 31P{1H}-NMR spectrum of complex 9 in CD3CN at room temperature

212

4.0

00

0

80

.81

1

3.5

40

7

7.9

84

5

Inte

gra

l

9.0

76

49

.06

43

9.0

52

39

.04

16

7.3

61

27

.33

85

7.3

14

47

.21

14

7.1

87

37

.16

19

7.1

37

86

.99

86

6.5

78

56

.56

78

6.5

55

86

.54

51

3.0

89

3

(ppm)

2.83.03.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.48.68.89.09.29.4

5.27

144.

0469

2.63

40

(ppm)-35-30-25-20-15-10-5051015202530354045

A-60. 1H-NMR spectrum of complex 10 in CD2Cl2 at room temperature

A-61. 31P{1H}-NMR spectrum of complex 10 in CD2Cl2 at room temperature

213

A-62. 1H-NMR spectrum of complex 11 in THF-d8 at room temperature

A-63. 31P{1H}-NMR spectrum of complex 11 in THF-d8 at room temperature

214

40.3

36

22.0

00

Inte

gral

8.04

537.

8768

7.83

407.

8112

7.42

057.

3617

7.31

757.

3028

7.20

117.

1717

7.14

637.

1262

3.85

773.

8484

3.83

903.

8336

3.82

703.

8015

3.79

083.

7320

3.69

723.

6651

3.65

973.

6530

3.61

293.

6075

3.60

083.

5808

3.57

543.

5701

(ppm)3.64.04.44.85.25.66.06.46.87.27.68.0

18

.68

18

7.9

12

76

.75

10

1.4

44

9

-2.6

99

5

-22

.29

12

-25

.77

63

(ppm)

-44-40-36-32-28-24-20-16-12-8-404812162024283236

A-64. 1H-NMR spectrum of complex 12 in CDCl3 at room temperature

A-65. 31P{1H}-NMR spectrum of complex 12 in CDCl3 at room temperature

215

39.4

25

4.0

000

3.9

703

9.5

162

3.9

182

Inte

gra

l

7.9

276

7.9

075

7.8

848

7.8

634

7.7

817

7.7

590

7.7

349

7.7

108

7.4

606

7.4

352

7.4

111

7.3

964

7.3

643

7.3

389

7.3

269

7.3

028

4.4

945

4.4

798

4.4

624

3.9

099

3.7

828

3.5

741

(ppm)

3.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.2

31.6

809

31.4

611

31.2

414

31.0

844

30.8

646

30.6

448

30.4

564

30.2

366

30.0

482

19.1

846

18.9

649

18.7

765

8.4

152

8.2

269

8.0

071

-2.3

228

-2.5

426

-2.7

623

(ppm)

-8-6-4-20246810121416182022242628303234363840

A-66. 1H-NMR spectrum of complex 13 in CDCl3 at room temperature

A-67. 31P{1H}-NMR spectrum of complex 13 in CDCl3 at room temperature

216

7.46

67

7.64

27

18.1

73

8.45

54

3.99

32

4.13

7610

.184

4.00

00

Inte

gral

7.92

497.

9129

7.90

627.

9008

7.89

427.

8875

7.88

217.

8620

7.53

567.

5129

7.49

687.

4741

7.47

007.

3175

7.30

157.

2734

7.24

937.

1837

7.15

977.

1342

4.10

394.

0905

4.07

714.

0624

3.86

843.

8631

3.85

773.

8042

3.56

213.

5554

3.55

00

(ppm)3.64.04.44.85.25.66.06.46.87.27.68.0

22

.98

38

22

.60

70

22

.29

30

12

.24

58

11

.96

32

11

.90

04

11

.58

64

1.5

39

11

.19

38

0.8

79

8

-1.4

12

2-1

.78

90

-1.8

83

2-2

.19

72

-2.2

60

0-2

.47

98

-2.5

73

9-2

.85

65

-2.9

82

1-3

.32

75

-5.2

74

2-5

.55

67

-5.9

33

5-6

.05

91

-6.3

41

7-6

.65

56

-6.7

18

4-7

.03

24

-7.1

26

6-7

.50

34

(ppm)

-12-10-8-6-4-20246810121416182022242628

A-68. 1H-NMR spectrum of complex 14 in CDCl3 at room temperature

A-69. 31P{1H}-NMR spectrum of complex 14 in CDCl3 at room temperature

217

40

.26

2

8.1

19

1

10

.15

1

4.0

00

0

Inte

gra

l

7.7

64

47

.74

43

7.6

40

07

.61

72

7.5

98

57

.57

71

7.4

05

87

.38

17

7.3

42

97

.32

02

7.2

96

1

3.9

64

8

3.8

10

9

3.5

50

0

(ppm)

3.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.4

22

.88

96

22

.63

84

22

.35

58

12

.74

81

12

.46

55

12

.18

30

2.5

75

32

.29

27

2.0

10

1

-5.7

45

1-6

.02

77

-6.3

10

3

-13

2.2

46

4

-13

8.1

17

7

-14

3.9

89

1

-14

9.8

60

5

-15

5.7

31

8

(ppm)

-155-145-135-125-115-105-95-85-75-65-55-45-35-25-15-55152535

A-70. 1H-NMR spectrum of complex 15 in CDCl3 at room temperature

A-71. 31P{1H}-NMR spectrum of complex 15 in CDCl3 at room temperature

218

39

.24

4

3.9

55

8

4.1

37

8

10

.00

0

4.0

92

1

Inte

gra

l8

.14

70

8.1

26

98

.12

03

8.1

12

28

.10

82

8.1

01

58

.08

15

7.8

40

67

.81

66

7.7

99

27

.77

51

7.3

51

07

.33

63

7.3

06

87

.28

14

7.1

94

47

.15

97

7.1

34

27

.11

01

4.4

08

9

4.3

30

04

.31

13

4.2

92

54

.21

36

3.8

61

73

.85

50

3.8

49

73

.82

16

3.5

29

93

.52

46

3.5

17

9

(ppm)

3.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.2

39

.27

92

39

.02

80

38

.74

54

21

.82

20

21

.57

09

17

.64

62

17

.36

36

17

.11

24

16

.61

00

16

.32

75

16

.07

63

15

.54

25

15

.25

99

15

.00

88

11

.11

54

10

.86

43

10

.55

03

0.1

89

0-0

.09

35

-0.3

44

7

-6.1

21

9-6

.37

31

-6.6

24

3

(ppm)

-16-14-12-10-8-6-4-20246810121416182022242628303234363840424446

A-72. 1H-NMR spectrum of complex 16 in CDCl3 at room temperature

A-73. 31P{1H}-NMR spectrum of complex 16 in CDCl3 at room temperature

219

20

.84

87

20

.66

03

20

.47

19

19

.90

68

19

.71

84

19

.49

86

14

.85

18

4.7

41

7

-5.3

68

3

-13

3.2

82

5

-13

9.1

53

9

-14

5.0

25

2

-15

0.8

96

6

-15

6.7

36

6

(ppm)

-155-145-135-125-115-105-95-85-75-65-55-45-35-25-15-551525

41

.62

2

1.9

97

1

1.8

73

2

2.0

41

4

1.9

71

3

5.0

10

0

5.0

00

0

1.9

79

3

1.9

63

9

Inte

gra

l

8.0

85

58

.06

54

8.0

45

38

.02

39

7.8

83

57

.86

07

7.8

38

07

.81

66

7.7

97

87

.77

91

7.7

60

47

.57

04

7.5

46

37

.53

96

7.5

19

57

.49

28

7.4

74

17

.44

33

7.4

24

67

.37

51

7.3

51

07

.32

02

7.2

92

17

.24

13

7.2

15

87

.19

58

7.1

83

77

.15

70

7.1

32

9

4.4

49

14

.42

90

4.4

10

34

.38

89

4.3

67

54

.34

87

4.3

30

04

.09

45

4.0

30

34

.02

50

4.0

18

33

.87

24

3.7

57

43

.70

65

3.6

86

53

.67

98

3.6

74

43

.60

75

(ppm)

3.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.4

A-74. 1H-NMR spectrum of complex 17 in CDCl3 at room temperature

A-75. 31P{1H}-NMR spectrum of complex 17 in CDCl3 at room temperature

220

40

.74

1

9.9

88

5

12

.00

0

Inte

gra

l

7.9

46

3

7.4

44

6

7.1

93

17

.15

97

7.1

39

6

3.9

00

5

3.7

44

0

(ppm)

3.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.48.68.89.0

16

.39

03

16

.10

77

15

.13

43

14

.85

18

14

.56

92

14

.47

50

13

.90

98

13

.62

73

13

.31

33

3.2

66

02

.98

34

2.6

69

5

-7.3

77

8-7

.66

04

-7.9

74

4

(ppm)

-11-10-9-8-7-6-5-4-3-2-1012345678910111213141516171819202122

A-76. 1H-NMR spectrum of complex 18 in CDCl3 at room temperature

A-77. 31P{1H}-NMR spectrum of complex 18 in CDCl3 at room temperature

221

40

.11

0

22

.00

0

Inte

gra

l

8.0

44

08

.02

53

7.9

49

0

7.6

03

87

.58

51

7.5

69

07

.54

50

7.4

50

07

.35

90

7.3

05

57

.19

18

7.1

38

27

.13

02

7.0

55

37

.03

12

7.0

05

8

4.0

27

6

3.8

96

53

.87

51

3.8

69

83

.86

31

3.7

46

73

.61

02

(ppm)

3.03.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.48.68.8

37

.08

13

36

.79

87

36

.51

62

13

.87

84

13

.59

59

13

.34

47

13

.06

21

12

.71

67

12

.65

39

12

.27

72

3.1

09

02

.82

65

2.5

75

3

-7.6

60

4-7

.94

30

-8.1

94

1

(ppm)

-20-18-16-14-12-10-8-6-4-2024681012141618202224262830323436384042444648

A-78. 1H-NMR spectrum of complex 19 in CDCl3 at room temperature

A-79. 31P{1H}-NMR spectrum of complex 19 in CDCl3 at room temperature

222

7.9

37

4

12

.08

2

13

.94

4

3.9

80

8

6.0

00

0

Inte

gra

l7

.89

55

7.8

87

47

.88

21

7.8

76

77

.86

74

7.8

59

37

.85

00

7.4

51

37

.44

73

7.4

43

37

.44

06

7.4

36

67

.42

99

7.4

25

9

3.9

11

23

.90

32

3.8

60

43

.85

37

3.8

48

3

2.4

54

32

.41

01

2.3

98

12

.38

60

2.3

41

9

(ppm)

2.02.22.42.62.83.03.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.2

10

.58

17

0.0

32

1

-10

.51

76

(ppm)

-30-28-26-24-22-20-18-16-14-12-10-8-6-4-2024681012141618202224262830

A-80. 1H-NMR spectrum of complex 20 in CDCl3 at room temperature

A-81. 31P{1H}-NMR spectrum of complex 20 in CDCl3 at room temperature

223

A-82. 1H-NMR spectrum of complex 21 in CDCl3 at room temperature

A-83. 31P{1H}-NMR spectrum of complex 21 in CDCl3 at room temperature

224

A-84. 1H-NMR spectrum of complex 22 in CDCl3 at room temperature

A-85. 31P{1H}-NMR spectrum of complex 22 in CDCl3 at room temperature

225

7.4

36

67

.41

38

7.4

08

5

7.3

91

17

.37

77

7.3

55

07

.35

10

7.2

19

87

.21

18

7.1

83

7

7.1

58

37

.13

56

7.1

30

2

7.1

06

17

.09

94

7.0

88

77

.07

94

7.0

60

67

.05

53

6.9

91

1

6.9

67

0

6.9

49

66

.94

42

6.9

38

96

.92

68

6.9

01

4

6.8

80

0

(ppm)

6.646.686.726.766.806.846.886.926.967.007.047.087.127.167.207.247.287.327.367.407.447.487.527.567.607.647.687.727.76

41

.41

42

41

.19

44

40

.22

11

40

.03

27

26

.62

59

26

.43

75

26

.28

05

26

.09

21

12

.43

41

12

.21

44

11

.77

48

11

.58

64

(ppm)

56789101112131415161718192021222324252627282930313233343536373839404142434445

A-86. 1H-NMR spectrum of complex 23 in CDCl3 at room temperature

A-87. 31P{1H}-NMR spectrum of complex 23 in CDCl3 at room temperature

226

30

.85

4

4.0

52

1

2.0

00

0

Inte

gra

l

7.7

97

87

.79

38

7.7

87

17

.77

91

7.7

75

17

.76

84

7.7

61

77

.75

63

7.7

51

07

.74

30

7.7

32

37

.72

42

7.3

38

97

.31

35

7.2

94

87

.28

81

7.2

80

0

7.0

33

97

.02

85

7.0

19

27

.00

98

2.6

08

12

.57

47

2.1

06

42

.09

04

2.0

48

92

.03

28

2.0

15

41

.96

06

1.9

41

9

(ppm)

1.82.02.22.42.62.83.03.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.28.48.6

18

.71

37

18

.58

81

15

.98

21

15

.82

51

4.9

30

14

.80

45

3.2

66

03

.14

04

-8.8

53

5-8

.97

91

-9.4

18

6-9

.57

56

(ppm)

-14-13-12-11-10-9-8-7-6-5-4-3-2-1012345678910111213141516171819202122

A-88. 1H-NMR spectrum of complex 24 in CDCl3 at room temperature

A-89. 31P{1H}-NMR spectrum of complex 24 in CDCl3 at room temperature

227

19

.71

5

29

.64

5

8.0

50

6

4.0

00

0

Inte

gra

l7

.90

90

7.9

01

07

.88

63

7.8

74

27

.86

62

7.8

04

67

.77

66

7.6

78

97

.67

22

7.6

52

17

.64

81

7.0

20

67

.00

73

7.0

03

36

.99

92

6.9

02

96

.89

49

6.8

74

86

.84

94

6.8

29

36

.80

93

6.7

81

2

2.2

40

4

1.6

78

5

(ppm)

1.61.82.02.22.42.62.83.03.23.43.63.84.04.24.44.64.85.05.25.45.65.86.06.26.46.66.87.07.27.47.67.88.08.2

17

.89

58

17

.67

60

17

.23

65

17

.04

81

4.3

00

64

.04

94

3.8

29

6

-8.9

17

8-9

.13

76

-9.6

40

0-9

.85

97

(ppm)

-14-12-10-8-6-4-2024681012141618202224

A-90. 1H-NMR spectrum of complex 25 in C6D6 at room temperature

A-91. 31P{1H}-NMR spectrum of complex 25 in C6D6 at room temperature

228

3.97

86

3.96

28

12.2

05

3.00

09

4.01

26

3.01

19

2.00

00

Inte

gral

7.98

227.

9543

7.92

367.

7116

7.70

567.

6853

7.67

987.

6502

7.09

857.

0777

7.02

407.

0043

6.99

996.

9807

2.83

572.

8110

2.77

002.

7448

2.70

092.

6812

2.20

622.

1662

2.14

052.

0999

1.93

781.

9257

1.90

601.

8945

1.87

201.

8660

1.69

401.

6200

1.54

44

(ppm)1.52.02.53.03.54.04.55.05.56.06.57.07.58.0

22.4

302

22.1

742

20.2

476

19.9

915

8.60

298.

3468

7.40

797.

1641

-5.1

635

-5.4

195

-5.4

683

-5.7

244

(ppm)-8-6-4-2024681012141618202224

A-92. 1H-NMR spectrum of complex 26 in C6D6 at room temperature

A-93. 31P{1H}-NMR spectrum of complex 26 in C6D6 at room temperature

229

17.0

23

22.0

76

5.97

86

7.91

66

4.00

00

Inte

gral

8.02

818.

0214

8.00

277.

9987

7.86

497.

8595

7.83

687.

8328

7.82

487.

8087

7.80

33

7.10

637.

0809

7.05

687.

0407

7.01

676.

9765

6.95

246.

9297

2.58

962.

5735

2.51

732.

5106

2.50

262.

4464

2.43

042.

2618

1.81

631.

7413

1.66

91

(ppm)2.02.53.03.54.04.55.05.56.06.57.07.58.08.5

21.9

461

21.8

205

8.72

778.

5393

8.35

09

-4.7

419

-4.8

675

(ppm)-6-4-2024681012141618202224

A-94. 1H-NMR spectrum of complex 27 in C6D6 at room temperature

A-95. 31P{1H}-NMR spectrum of complex 27 in C6D6 at room temperature

230

2400 2200 2000 1800 1600 1400 1200 1000 800 60010

20

30

40

50

60

70

2110

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-96. IR (KBr) spectrum of complex 5

2400 2200 2000 1800 1600 1400 1200 1000 800 6000

10

20

30

40

50

60

70

2091

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-97. IR (KBr) spectrum of complex 6

231

2400 2200 2000 1800 1600 1400 1200 1000 800 600

40

50

60

70

2110

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-98. IR (KBr) spectrum of complex 12

2400 2200 2000 1800 1600 1400 1200 1000 800 600

30

40

50

60

70

80

2112

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-99. IR (KBr) spectrum of complex 13

232

2400 2200 2000 1800 1600 1400 1200 1000 800 60020

30

40

50

60

70

80

2106

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-100. IR (KBr) spectrum of complex 14

2400 2200 2000 1800 1600 1400 1200 1000 800 600

30

40

50

60

70

80

20742118

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-101. IR (KBr) spectrum of complex 15

233

2400 2200 2000 1800 1600 1400 1200 1000 800 60035

40

45

50

55

60

65

70

75

2107

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-102. IR (KBr) spectrum of complex 16

2400 2200 2000 1800 1600 1400 1200 1000 800 60010

20

30

40

50

60

70

80

2026

1967

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-103. IR (KBr) spectrum of complex 17

234

2400 2200 2000 1800 1600 1400 1200 1000 800 60020

30

40

50

60

70

80

2118

1953

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-104. IR (KBr) spectrum of complex 18

2400 2200 2000 1800 1600 1400 1200 1000 800 60020

30

40

50

60

70

80

90

100

21071953

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-105. IR (KBr) spectrum of complex 19

235

2400 2200 2000 1800 1600 1400 1200 1000 800 600

40

50

60

70

2110

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-106. IR (KBr) spectrum of complex 20

2400 2200 2000 1800 1600 1400 1200 1000 800 60040

50

60

70

80

1741

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-107. IR (KBr) spectrum of complex 21

236

2400 2200 2000 1800 1600 1400 1200 1000 800 600

40

50

60

70

80

1748

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-108. IR (KBr) spectrum of complex 22

2400 2200 2000 1800 1600 1400 1200 1000 800 600

40

50

60

70

80

2161

1721

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-109. IR (KBr) spectrum of complex 23

237

2400 2200 2000 1800 1600 1400 1200 1000 800 6000

10

20

30

40

50

60

70

2160

1719

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-110. IR (KBr) spectrum of complex 24

2400 2200 2000 1800 1600 1400 1200 1000 800 60010

20

30

40

50

60

70

80

1758

Tran

smitt

ance

(%)

Wavenumber (cm-1)

A-111. IR (KBr) spectrum of complex 25

238

2400 2200 2000 1800 1600 1400 1200 1000 800 600

20

40

60

80

100

2196

1749

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-112. IR (KBr) spectrum of complex 26

2400 2200 2000 1800 1600 1400 1200 1000 800 6000

20

40

60

80

100

1705

Tra

nsm

ittan

ce (%

)

Wavenumber (cm-1)

A-113. IR (KBr) spectrum of complex 27