Mohammad A. Omary

Department of Chemistry,

University of North Texas

(from my post-doctoral work with Professor John Fackler at Texas A&M University)

Gold

Starting material in Fackler’s lab

NN

N

NN

N

Au Au

Au

R

R

RR = CH2PhTR(bzim)

N

NN

Au Au

Au

OR

RO

ORR'

R'

R'

TR(carb) R = Et, R' = p-Tol

Trinuclear Au(I) Complexes, TRAu:

TRAu + M+ ???

M=Ag; Tl

IT’S A WHOPPER!!

M

Au Au

Au

Au Au

Au

+

~ 4.0Ao

Ao

Ao

~3.2

M = Ag+ or Tl+

~ 3.0

Synthetic Strategy

Burini; Fackler; Omary’s; Staples et al. Inorg. Chem.2000, 39, 3158.

TRAu + M+ {(TRAu)2M+}

Au

AuAu M+

Au

AuAu Au

Au

Au M+ Au

AuAuAu

Au

AuAu

AuAuM+

Solvent X-

X-X-

Au

AuAu M+

Au

AuAu Au

Au

Au M+ Au

AuAuAu

Au

AuAu

AuAuM+

Solvent X-

X-X-

Burini; Fackler; Omary; Staples, et al. Inorg. Chem.2000, 39, 3158.

440 460 480 500 520 540 560 580 600 620 640 660 680 700

Wavelength, nm

Lu

min

esce

nce

In

ten

sity

, a

. u

.

{Ag[Au(bzim)]3}BF4

Green glow at RT

Orange glow at 77 K

RT

{Tl[Au(carb)]3}PF6

{Tl[Au(bzim)]3}PF6

* Nucleophilic or basic character to the trinuclear gold complexes.

•Analogy with cation- interactions: Dennis A. Dougherty, Science 1996, 271, 163.

• Why not a neutral Lewis acid ?- TRHg: Hg3(C6F4)3

F

F

F

F

Hg

Hg

Hg

F

F

F

F

F

F

F

F

NN

N

NN

N

Au Au

Au

R

R

RR = CH2PhTR(bzim)

N

NN

Au Au

Au

OR

RO

ORR'

R'

R'

TR(carb) R = Et, R' = p-Tol

OR

Intercalates

TRHg

{(TRAu)2(TRHg)}

SUPER WHOPPER!!

Burini; Fackler; Omary; Staples et al. J. Am. Chem. Soc. 2000, 122, 11264-11265.

SUPRAMOLECULAR CHAIN ASSEMBLIES

{(TR(carb))2(TRHg)}

Extended-chain structure for {(TR(carb))2(TRHg)}

DFT Calculations of Trinuclear Complexes

Electrost. Pot. (a.u.)-0.0300 0.0300

[Au(bzim)]3[Hg(C6F4)]3

[Hg(C6F4)]3

green = positive

[Au(bzim)]3 red = negative

Electrostatic Potential Surfaces

Electrostatic interaction

ADF Calculations

[Au(carb)]3

MONOMER

-15

Elect rost . P

ot. ( kcal)

+15

ADF Calculations

{[Au(carb)]3}2

DIMER

-15

Elect rost . P

ot. ( kcal)

+15

Full Range (kcal/mol):

+23 -46 for dimer

+22 -34 for monomer

ADF Calculations

{[Au(carb)]3}2

DIMER

Green= positive

Red=negative

Luminescence spectra

15 17 19 21 23 25 27

Wavenumber/103cm-1

Inte

ns

ity,

arb

. un

its [TR(carb)]2[TRHg]

TR(carb)Average spacing

~ 1400 cm -1

Raman spectrum of a solution of TR(carb) in CH2Cl2 at RT

0

200

400

600

800

1000

1200 1300 1400 1500 1600 1700

Inte

nsi

ty,

arb

. u

nit

s

1422 cm-1

0

50

100

150

200

2750 2800 2850 2900

• Perhaps, closed-shell metallophilic interactions

play a role in stabilizing the supramolecular

structure!!

• Ultimate test for the basic behavior:

==> ORGANIC LEWIS ACIDS: C6F6; TCNQ

3.152 Å

Intramolecular Au…Au:3.475; 3.471; 3.534 Å3.152 ÅCharge transfer

complex indicated by:

- shortening of Au..Au

- intense color….

Omary; Fackler et al. J. Am. Chem. Soc. 2001, 123, 9689-9691.

0.0E+00

2.0E+02

4.0E+02

6.0E+02

8.0E+02

1.0E+03

400 500 600 700 800 900 1000

Wavelength, nm

, M

-1c

m-1

Omary; Fackler et al. J. Am. Chem. Soc. 2001, 123, 9689-9691.

Omary; Fackler et al. J. Am. Chem. Soc. 2001, 123, 9689-9691.

Emission spectra of TRIS versus exposure time to C6F6

vapor at ambient temperature and pressure

0

500

1000

1500

2000

2500

3000

3500

4000

4500

350 400 450 500 550 600 650

Wavelength, nm

Re

lati

ve

inte

ns

ity,

a.u

.

0

51

65

98

148

208

1322

1439

1441

1462

Exposure time, minutes

Omary; Fackler et al. J. Am. Chem. Soc. 2001, 123, 9689-9691.