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1973

The Crystal and Molecular Structures of Trans-Diiodotetrakis(para-Tolylisocyano)iron(ii) andTrans-HydridocarbonylTris(triphenylphosphine)cobalt(i): ChemicalBonding Implications.Johnnie Marie WhitfieldLouisiana State University and Agricultural & Mechanical College

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Recommended CitationWhitfield, Johnnie Marie, "The Crystal and Molecular Structures of Trans-Diiodotetrakis(para-Tolylisocyano)iron(ii) and Trans-Hydridocarbonyl Tris(triphenylphosphine)cobalt(i): Chemical Bonding Implications." (1973). LSU Historical Dissertations andTheses. 2582.https://digitalcommons.lsu.edu/gradschool_disstheses/2582

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WHITFIELD, Johnnie Marie, 1943- THE CRYSTAL AND MOLECULAR STRUCTURES OF TRANS-DIIODOTETRAKIS (PARA-TOLYLISOCYANO) IRON(II) AND' TRans-hydridocarbonyltri S (TRIPHENYLPHOSPHINE) - COBALT (I) : CHEMICAL BONDING IMPLICATIONS.The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1973 Chemistry, inorganic

University Microfilms. A XEROX Company, Ann Arbor, Michigan

THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED.

THE CRYSTAL AND MOLECULAR STRUCTURES OOF TRANS-DIIODOTETRAKIS(PARA-TOLYLISOCYANO)IRON(II)

ANDTRANS-HYDRIDOCARBONYLTRIS (TRIPHENYLPHOSPHINE ) COBALT (I)

CHEMICAL BONDING IMPLICATIONS

A DissertationSubmitted to the Graduate Faculty of the

Louisiana State University and Agricultural and Mechanical College

in partial fulfillment of the requirements for the degree of

Doctor of Philosophyin

The Department of Chemistry

byJohnnie Marie Whitfield

B.S., Millsaps College, I965December, 1973

IN MEMORIAM

THELMA SELLERS TRTCHE and

RHODA WHITFIELD

it

ACKNOWLEDGEMENT

To my beloved family and friends who helped to bring this endeavor to fruition immeasurable gratitude Is due. To my colleagues

a special thanks is given, with especial acknowledgements due to the following:

John Bourg for assistance in data collection and for computer advice;

Drs. J. Tracy Broussard and Joseph Wander for a high field NMR spectrum;

Steve Durkin and George Sexton for expert electronic repairs on the temperamental diffractometer;

Dr. Mary Good of Louisiana State University at New Orleans for Mossbauer data;

Dr. J. P. Maher of the University of Bristol, England, for the iron compound crystals;

Henry Streiffer for computer programming guidance and assistance in implementing the major X-ray system;

George Tupper for patiently synthesizing cobalt hydride crystals until we had a winner.

Financial assistance in the publication of this Dissertation was generously furnished by the Charles E. Coates Memorial Fund of the Louisiana State University Foundation donated by George H. Coates.

Part of this work was done under a Cities Service Fellowship. These sources of support are gratefully acknowledged.

Thanks to my grandfather, the late Benjamin F Whitfield, my introduction to mineralogy occured as a toddler. An educated

ill

gentLeman-farmer and naturalist, he amassed a truly great eclectic collection during his lifetime. My favorite portion of his acquisi­tions (which ranged from antlers and arrowheads to yokes and zircons) was his massive assortment of rocks (both gravel and gemstone variety). His greatest legacy to me was that, In sharing these treasures and their individual histories with me, he instilled a great love and fascination for the marvels and mysteries of minerals and their beautiful crystalline forms.

Finally, I salute my major professor, Dr. Steven F. Watkins. As your first graduate student, I was able to share the joys and frustrations of ordering, uncrating, installing, and finally operating the X-ray lab equipment; of debugging and initiating the numerous computer support programs; of solving the first crystal structure at LSU-BR. My initiation into crystallography was highlighted with your youthful enthusiasm, patience, and expert guidance. Thank you for both teaching me the rudiments of the field and sharing your technical expertise with me during these truly memorable years.

iv

FOREWORD

Exploring the intricacies of selected transition metal organometalllc compounds' molecular and crystal structures has been quite an undertaking. As the first graduate student of Professor

Steven F. Watkins, X was able to learn the theory and techniques of X-ray crystallography while also helping to establish the Chemistry Department’s X-Ray Facility at Louisiana State University at Baton Rouge. The initial challenge lay in installing the single crystal equipment for both camera work and semi-automatic diffractometer data collection, and also in initiating suitable support facilities prior to investigating the structures.

Installation of the equipment made by Enraf-Nonius was easily accomplished, but the three circle diffractometer took nine months to become completely operational and has had numerous major breakdowns in its four years of service. The minor task of collecting supplies and equipment for recrystallization, crystal mounting, film developing, density determinations, and crystal orientation was over­shadowed by the implementation of the computer support programs for

the crystallographic data. Though most of the programs were obtained from crystallographic groups at the University of Maryland, University of Wisconsin, Oak Ridge National Laboratory, and Brookhaven National Laboratory, it was necessary to make these programs compatible with the IBM 360-65 available for use as well as with the data collected within the lab.

Interwoven with the organization of the X-ray lab was the solution of the structure of FeI£.(CNC6H4CH3)4. No major step in the

v

collecting and handling of data was taken without first standardizing the equipment, debugging a computer program, or loiprovlzing a path around a mechanical malfunction, A second compound, [(CH3 )3Ge(CO)3- RuGe(CH3)2]2 , was begun (see Appendix) while work was in progress on the first one. But it was abandoned as soon as another member of the group, Madeleine Grozat Williams, solved the structure of its silicon analogue, initially mistaken for a different compound, due to an in­correctly labeled sample vial. The structure of a third compound,

CoH(CO)[P(CsH5 )3 ]3 t was then attempted. When this compound started exhibiting crystal instability, a fourth compound, (C12HioN2+ )(Br"), dihydrophenazonium bromide, a deep blue-purple free radical, was investigated. Work on this fourth compound and its chloride deriva­tive, prepared by Jon Sherrill and Dave Durrett of X.SU-BR, was finally abandoned when crystals suitable for data collection could not be pre­

pared, major problems being twinning, glass and needle formation, and the inability to recrystallize due to low solubility and instability in solution. In the meantime, the crystal problems connected with the cobalt hydride were solved, a suitable crystal isolated, and data collected over a seven-month period.

The first and third compounds are therefore the subject of

this Dissertation. These two first row transition metal organometalllc compounds have been examined by X-ray crystallographic methods and their crystal and molecular structures solved. One metal is univa­lent and five coordinate, the other is bivalent and six coordinate.

One is a d6 system, the other is a d8 system; and when taken with their respective ligands, both obey the 18 electron rule. For both

compounds the molecular geometry is bipyramidal; for one it is trigonal,

vi

for the other tetragonal. In both cases the organic ligands occupy equatorial plane positions with the other two ligands in the axial positions*

vll

TABLE OF CONTENTSPAGE

ACKNOWLEDGEMENT.............................................. ill

FOREWORD..................................................... vLIST OF TABLES............................................... ixLIST OF FIGURES.............................................. xABSTRACT..................................................... xiI. TRANS-DIIODOTETRAKIS{ PARA-TOLYLISOCYANO) IRON( II)

A. Introduction. ........... 2B. Experimental........................................ 6

C. Crystal Data........................................ 10D. Solution of the Structure.............. 12E. Discussion.......................................... 23F. References.......................................... 39

II. TRANS -HYDRIDOCARBONYLTRIS ( TRIPHENYLPHOSPHINE) COBALT (l)

A. Introduction........................................ ^5B. Preparation......................................... ^5C . Experimental........................................ ^7

D. Crystal Data........................................ 53E. Solution of the Structure..........................

F. Discussion.......................................... 79G. References.......................................... 83

APPENDIX..................................................... 92

VITA......................................................... 97

viii

LIST OF TABLES

TABLE PAGEI-I ATOMIC COORDINATES AND TEMPERATURE FACTORS FOR

THE FeIa(CNC6HgCH3 ) 4 MOLECULE...................... 17I-II RIGID-BODY RING PARAMETERS FOR THE

FeI2(CNC6H4CH3 ) 4 MOLECULE.......................... 19I-III INTRAMOLECULAR BOND LENGTHS AND BOND ANGLES

FOR FeI2 (CNC6H4CH3 ) 4............................... 21I-IV FeI2 (CNCeH4CH3) 4 STRUCTURE FACTOR TABLE............ 23

II-1 SUBROUTINE EZEOUT.................................. 31II-II ATOMIC COORDINATES AND TEMPERATURE FACTORS

FOR THE CoH(CO)[p(C6H5 ) 3 ]3 MOLECULE............... 62II-III RIGID-BODY RING PARAMETERS FOR THE

CoH(CO)[p(C6Hs ) 3 ] 3 MOLECULE....................... 6k

II-IV ATOMIC COORDINATES OF THE MEMBERS OF THE RIGID-BODY RINGS IN THE MOLECULE CoH(CO)CP(CeH5)3 ]3..„... 66

II-V INTRAMOLECULAR BOND LENGTHS AND BOND ANGLESFOR COH(CO)[P(C6H5 ) 3 ] 3 ............................. 70

II-VI CoH(CO) CP{C6H5 ) 3 ] 3 STRUCTURE FACTOR TABLE........ 72

II-VII INTRAMOLECULAR AND INTERMOLECULAR CONTACTDISTANCES ^ 2.60S FOR CoH(CO)[p(CsH5 ) 3 ] 3 ...... tfc

II-VIII FIVE-COORDINATE TRANSITION METAL HYDRIDES.......... 86

A-I CRYSTAL DATA COMPARISON FOR THREER u a A ^ 6Hao03 MOLECULES............................ 9I1-

ix

LIST OF FIGURESFIGURE PAGEl-l SCHEMATIC MOLECULAR ORBITAL DIAGRAM FOR D ^

MODEL OF CoI2(GNCeH4CH3)4............... „......... 41-2 ORTEP DRAWING OF THE FeI2(CNCeH4CH3)4

MOLECULE........................................... 151-3 ORTEP STEREOSCOPIC DRAWING OF THE

FeI2(CNC6H4CH3)4 MOLECULE.......................... 291-4 [100] PLANAR PROJECTION OF THE UNIT CELL OF

FeI2(CNCeH4CH3)4................................... 311-5 [001] PLANAR PROJECTION OF THE UNIT CELL OF

FeI2(CNC6H4CH3)4............................ 331-6 SCHEMATIC MOLECULAR ORBITAL DIAGRAM FOR Dgd

MODEL OF FeI2(CHCeH4CH3)4.......................... 351-7 METAL-LIGAND TT INTERACTIONS IN FeI2(CNC6H4CH3 )4.... 37

2-1 ORTEP DRAWING OF THE CoH(CO) [P(C0H5 ) 3 ] 3 MOLECULE... 58

2-2 ORTEP STEREOSCOPIC DRAWING OF THECoH(CO)[P(C^H5 ) 3 ] 3 MOLECULE............ 60

2-3 ORTEP STEREOSCOPIC DRAWING OF THE COBALTCOORDINATION SPHERE ........ 80

2-4 ORTEP STEREOSCOPIC DRAWING OF THETRIPHENYLPHOSPHINE LIGAND.......................... 82

x

ABSTRACT

Trana-d ilodotetrakls(para-toly1i socyano)iron(II), FeI2 (CNCeH4CH3 )43 Is a low spin da complex with S4 molecular sym­metry. Analysis of three dimensional single crystal X-ray diffracto­meter data collected by the 0 - 2 0 scan technique reveals four molecules per tetragonal unit cell of dimensions a=b=l4. 5 00(7 )8 , c=l5 .690(18)8, and space group l4i/a. Refinement was based on full matrix least squares techniques for 7&5 observed reflections with a final weighted R factor of 5.2$. The Fe-I bond distance of 2 .6 5 2(5 ) 8 is signifi­cantly shorter than the analogous Co-I bond length of 2 .6 9 2(6 )8 , implying that in the d7 system the additional electron occupies thed 2 orbital rather than the d 2 2 orbital. While the four isocyanoz xligands deviate slightly from a square planar arrangement, Mossbauer data indicate substantial "back bonding" with the Iron.

Trans-hydridocarbonyItris(triphenylphosphine)cobalt(i), CoH(C0 )[p(C6H5)3 ]3 , has been analyzed by three dimensional single crystal X-ray diffractometer data collected by the 0-20 scan technique. Each monoclinic unit cell contains four molecules. The space group

is P2 x/c with cell dimensions of a=17*072(l4)8, b=11.4ll(8)8, c=25.044(24)8, and 0=107.41(7)8. The structure was solved using direct methods in conjunction with Patterson and Fourier techniques. After rigid body full matrix least squares refinement of 1900 reflec­tions the hydride ligand was observed in a difference Fourier synthesis. Final refinement resulted in a weighted R factor of 3 -8$. The cobalt coordination polyhedron is a trigonal blpyramid with the three phos- phoruB atoms in the equatorial plane. The cobalt atom lies O.3I8 from

xi

this plane toward the axial carbonyl ligand. The hydride occupies

the remaining trans-axial position of the bipyramid. The Co-H dis­tance is 1.41(9)8; the Co-P bond lengths are 2 .1 76(5)8 , 2.19^ 5)8 , and 2.195(^)-8; and the Co-C distance is 1.70(2)8.

xii

X

TRANS-DXIODOTETRAKIS(PARA-TOLYLISOCYANO)IRON(II)

1

INTRODUCTION

Trans-diiodotetrakis(para-tolylisocyano)cobalt(II),CoIs(CNC6H 4CH3 )4, has been prepared and the esr spectra for both thesolution and solid state studied by Maher. x *s He proposed that the

order of the molecular orbital energy levels was Jdw < 3d„_,xy xz3d < 3dza < 3dx2_y2. Thus for molecular symmetry the approxi­mate molecular diagram for this d7 cobalt compound would be as shown

in Figure 1-1, with the unpaired electron occupying the A^g* (^z£ anti-bonding) orbital. Gilmore, et al., examined the molecular struc­ture of this-cobalt(II) complex by use of single crystal X-ray diffraction film techniques. 3 The resulting structural data of Gilmore, however, were not sufficient to establish the validity of Maher's assignment of the order of the molecular orbital energy levelB.

It was felt that if the unpaired electron could be removed either by oxidation of the Co(ll) to Co(ill) or by replacement of the Co(ll) with Fe(ll) (both methods resulting in a de metal ion), the X-ray structural analysis of the d6 system would definitively estab­lish the order of the molecular orbital energy levels, particularly the anti-bonding and d^g. If the unpaired electron occupiesthe d 2 2 orbital, then upon its removal the metal-carbon bond shouldx -ybecome shorter. If, however, the d 2 orbital were lower in energy,zremoval of the unpaired electron results in a shortening of the metal-

iodine bond.When trans-diiodotetrakis(para-tolylisocyano)iron(II),

FeI2 (CHCeH4CH3)4, was prepared, this X-ray structural study was

2

5undertaken. In addition to elucidating the order of the energy levels, it waB hoped to explore the possibility of "back bonding" in the

FeCNCgH^Hg moiety.

FIGURE 1-1

SCHEMATIC MOLECULAR ORBITAL DIAGRAM FOR D ^ MODEL OF CoI^CNCsH^Ha) 4

Co(ll)ORBITALS

MOLECULARORBITALS

LIGANDORBITALS

_________ TT*(CNAr)*+P (A2u ,Eu )_______ _________ UNFILLED (A2g’A2uJ

------- ---- ---- (Alg,A2g* Blg,BIu’

B2g,E ) _ _ U B 5 LL

B, ,E , lu’ g 5

2E ) u

B0 *(d o o) 2g v x^-y^'

- — Ai g*<d^

yz-

*» (Alg) ------- ^ S u ’h s ’ Eg.Eu>

JU a(l)3d(Alg,Blg, ^ _ _ - J i Eg (dxz, _ n (Al g ,Asu)

li B, (d )U a(CNAr) (AlS’B2g ’

— li E u >

1J FILLEDti (BONDING)li____

EXPERIMENTAL

Deep purple crystals of trans-diiodotetrakls(para- tolylisocyano)iron(ll), Fels were furnished by Dr. J. P. Maher of University of Bristol, England. The well-formed octahedral crystals were prepared by reacting iron(ll) iodide with para-tolylisocyanide in ethanol and recrystallizing the product from methylene chloride.

Preliminary orientation and unit cell data were obtained from Weissenberg and precession photographs of an irregularly shaped

crystal using molybdenum Ko- radiation, \ = 0.7101&. These photo­graphs yielded a monoclinic cell, but strong evidence of tetragonal symmetry was displayed in one precession zone. A second crystal, which later proved to be twinned, was used to obtain approximate cell parameters in the tetragonal system. A transformation matrix was then derived, and the monoclinic cell was found to be mounted with the b axis along the (1 1 1) body diagonal of the tetragonal cell:

/ s \a5

Wk s k

k 1p. 12

-l 1 0/ /■

initialmonoclinic

cellconventionaltetragonal

cell

The space group, as determined from these films, was ihj/amd (Dj^i No. lhl) . 4

The irregularly shaped tetragonal crystal, with approximate dimensions 0.2mm x 0.2mm x O.ljmm, was then aligned on an Enraf Nonius

6

PAD-5 four circle diffractometer with the C m ] direction colinear with the phi axis. Three reflections, -4 1 5 , -4 4 0, and 5 5 0 , were well centered and used as the defining reflections for ORIENT.5 While centering ten reflections of high two theta values (mean = 18.5°), reflections were observed which destroyed an apparent (pseudo-)mirror in the film data, thus eliminating l4i/amd as the space group and establishing l4j./a (Cj^, No. 88)4 as the correct space group, with systematic presences h + k + 1 = 2n for all hkl reflections, h = 2n and k = 2n for hkO, and 1 = In for 001. The ten well-centered reflec­tions were input into the PARAM link of XRAY '67 with initial cell parameters of a = b = 14.5268 and c = 15-737'S. 6 These parameters were subjected to a nonlinear least squares fit and converged in two cycles.

Utilizing the three orientation defining reflections 10 0 0, 0 10 0, and 0 0 4, DIFSET generated diffractometer control cards for 1474 reflections.7 The theta scan rate was half a degree per minute with a two theta scan range, SR, calculated by:

SR = 1.800 + 1.000* tan (e).

Optimization time was 5 seconds, and the initial and final background times were both 20 seconds. Three standards, 8 8 0, 6 5 5 , and 5 5 6 , were inserted in the control deck after every 100 reflections.

The card controlled diffractometer was programmed to posi­tion a given hkl reflection at the peak theta value; make backlash corrections in theta, phi, and chi; optimize the photon count rate with 10 attenuators; decrease theta approximately one-half degree to the beginning of the theta-two scan; take a 20-second background count; start the scan; and terminate with an additional 20-second background

count. Unfortunately, the optimization procedure started malfunc­tioning after the first few reflections and it became necessary to optimize manually. In addition, the keypunch interface proved to be defective and data collection had to proceed via a strip chart re­corder, a semi-reliable teletype, and extensive manual notes. After the first one-hundred reflections, which were not exceptionally well- centered in the scan range, it was decided that manual omega maximization would improve the data. If, during the omega maximiza­tion, the peak height was less than l.J times the background or base line on the recorder, the reflection was rejected and listed as un­observed. This resulted in many high theta angle reflections of relatively low Intensity being discarded; a total of k$0 of the 1U7^ reflections were deleted or rejected in this way.

The recorded data were edited and punched on Hollerith cards. These cards were then utilized in the data reduction program written specifically for the Enraf Nonius PAD- 3 Diffractometer, DIFDAT.8 DIFDAT reduced the Intensity (i) to the structure factor modulus (fq) by applying the standard Lorentz-polarization correction (Lp), and calculated an estimated standard deviation o(l) by the formula

o2{l) = cgcan + Cbgl + Cbg2^ *

In this formula the integrated photon count C is given for both the scan and the initial and final backgrounds (bgl and bg2, respectively) and the corresponding times for these counts (T) in seconds is uti­

lized.

If the reduced Intensity was found to be less than or equal to 2 o(l), the reflection was classed as unobserved. There were 870 observed reflections. The Fo's ant* their corresponding standard de­viations o ( f ) , estimated by the formula

a(F) = S iI2 (l*Lp) 3

were then calculated. The I36 redundant and equivalent reflections were subjected to a weighted averaging procedure and the resulting 68

reflections inserted in their place. After final editing of all the reflections, there were 765 observed reflections ready for use in solving the crystal and molecular structure of FeI2 (CNC6H4CH3)4.

CRYSTAL DATA

Trans-dilodotetrakla {para-toly1Isocyano)iron(II), FeIe(CNCeH4CH3)4, has a molecular weight of 777*29 g/mole. It con­tains four molecules per tetragonal unit cell of dimensions a •» b « lL.500(7)8*, c = 1 5.6 90(1 8)8 , and V - 3 2 9 8.8 8.3 The space group Is iL-i/a. The theoretical density Dc was calculated to be I . 56 5 g/cm3 , and compared well with the experimental density of I . 5 6 g/cra3 determined by flotation.

Because of the unit cell occupancy by four molecules, the Iron and iodine atoms were forced by symmetry restrictions on iLi/a to occupy special positions. The iodine atoms occurred in the 8e special positions, but the iron atom could occupy either the La or Lb special'positions. 4 There was no difference in 4a or Lb other than the absolute orientation of the molecule with respect to the cell.The iron was placed in La at the inversion center of the L axis at 1/8 along c, and the iodine atoms were located above and below the iron along the L axis. The origin of the cell was located on an inversion

center.The centrosymmetrlc body centered unit cell, reduced to its

primitive reduced cell by REDUCELL, 9 has cell constants a = b “ c = 12.98, a = IO5.1°, and fl - y - 111.7°. The transformation matrix to the reduced cell i3 given by

*The numbers in parentheses, both here and throughout this Disserta­tion, represent the estimated standard deviations for the last significant figure.

10

11

i \ /•

b = ■

'cl \reducedcell

tetragonalcell

SOLUTION OF THE STRUCTURE

The reduced data, which were now compatible with the crystallographic computing master program, XRAY '67, 0 were loaded on tape. Atomic scattering factors used were those calculated by Hanson, et al.10 A Patterson synthesis revealed the predicted vectors arising from the iron and iodine atoms occurring in the special positions 4a and 8e, respectively. Calculations based on this choice of locations for these atoms produced calculated structure factors (Fc). The Fc 's were then compared with the observed structure factors 0 ?Q) to produce a residual index (r) of 0-324, determined by the formula

_ slIf0I - K,ll £1*^1 '

Since the iron atom was located on the 4a special position (the inversion center of the T+ axis), it was necessary to locate only one-fourth of the molecule. The 16 symmetry operations of the unit cell would generate 16 asymmetric units. With four asymmetric units per molecule, this produced the required four molecules per unit cell.

From a map produced by a Fourier difference synthesis the atoms of the isocyanide group and the phenyl ring were found. After nine cycles of block diagonal least squares the R value was 0.124. Another Fourier difference synthesis map yielded the remaining non­

hydrogen atom in the asymmetric unit, the phenyl ring’s methyl carbon. Each observed structure amplitude was weighted by the reciprocal of its variance:

1?and the weighted R value (wR) was calculated by the formula:

After four cycles of full matrix least squares a wR value of 0.090 was obtained.

At this point the phenyl group was treated as a rigid hexagon with all carbon-carbon bond distances constrained to be 1.397®* RBANG was used to calculate the orientation of the ring. 11

The origin was located at the center of the ring. (Subsequent treat­ment based on an origin which coincided with the coordinates for the ring carbon attached to the nitrogen resulted in the identical re­sults reported here.) A weighted, rigid-body full matrix least squares refinement was obtained by using ORFLSD, an extensively modified version of the Oak Ridge full matrix least squares refinement program, ORFLS. 13 The resulting wR was 0.09^. In comparing the iso­tropic rigid-body with the isotropic non-rigid-body model (constrained vs. unconstrained refinement), the Hamilton R factor ratio test13 sup­ports the validity of the isotropic rigid-body model with better than 9 9.5# confidence.

Prior to releasing the isotropic restraints on the tempera­ture factors of the iron and iodine atoms and converting to anisotropic temperature factors it was necessary to consider the symmetry restric­tions arising from their special positions within the unit cell.Using the method of Levy14 the following symmetry constraints were determined for the values of the six components of the symmetric thermal tensor:

wR =M I fJ - |Fc |)e

» | F j 2

1*4-for Iron: £11 = fizz $33 0; , 12 = ftis “ fls3 88 0;

for Iodine: fi2S 5 £33 ^ 0xs ^ Oi £13 = 0£3 = 0 .

Using the subroutine RESETB in ORELSD, these relationships were re­tained. After three cycles of full matrix least squares, wR was O.O8 5. Fluctuations were noted in the values of the anisotropic temperature component 0 n {~ ^zz) • These were not significant varia­tions as they occurred within a two sigma range of the mean which is reported in Table I-I.

Final editing of the data occurred at this point. Eight reflections, the initial measurements of which were questionable, were removed. After three cycles of OBFLSD,wR dropped to O.O5 2. At this point the four ring hydrogens were added with carbon-hydrogen bond distances of 1.00&. Following three cycles of refinement on 32

variable parameters (nv) for 765 observed reflections wR was 0.052 and R was 0.075. The error of fit (EOF) was 9-339> calculated by the formula

a, C|pJ - |f„|)»EOF5 = -------------- .^no-nvj

The maximum shlft-to-error ratio was O.Oh.Figure 1-2 contains a computer drawing produced by QRTEP

based on the final molecular parameters. 15 (Hydrogens are omitted for clarity.) The atomic coordinates, temperature factors, ring parameters, bond lengths, and bond angles are listed in Tables I-I through I-III. Table I-IV lists the calculated and observed structure factors for the appropriate hk£ reflections.

FIGURE 1-2

ORTEP DRAWING OF THE FeIe(CNC6H4CH3 )4 MOLECULE

(WITH 50# PROBABILITY ELLIPSOIDS)

CT\

TABLE I-I

ATOMIC COORDINATES AND TEMPERATURE FACTORS FOR THE FeI2(GNCsH4CH3 ) 4 MOLECULE

18

ATOMFRACTIONAL CELL COORDINATES ISOTROPIC

TEMPERATURE FACTOR, BX y z

Fe 0 .0 0 0 0 0 .2 5 0 0 0 .1 2 5 0 —

I 0 .0 0 0 0 0 .2 5 0 0 0.2928(1) —Cl 0.0997(12) 0 .1 5 9 5(1 2) 0.1160(13) 5-3(4)N 0 .154 3(10) 0 .1106(10) 0 .1131(1 0) 6.6(4)C2 0 .4 158(1 3) -0 .1 6 3 8(13) 0 .0 2 2 5(1 3) 7.6(5)CRl 0 .2 1 9 6 0 .0 4 4 3 O.O963 3-8(4)CR2 0 .3 1 3 7 0.0645 0 .0 9 8 6 6.3(5)CR5 0 .3 7 8 2 -0 .0 0 2 9 0.0763 7.4(6)CR4 0.3484 -0 .0 9 0 6 O.O5I6 6.5(5)CR5 0 .2 5 4 2 -0 .1 1 0 8 0.0493 6 .8 (5 )cr6 0 .1 8 9 8 -0.0434 0.0717 6 .8 (5)HR2 0 .3 3 5 0 0.1273 0 .1 1 6 3 7.0HR? 0 .4 4 5 6 0 .0 1 1 6 0.0779 7.0HR 5 0 .2 3 2 9 -0.1736 0.0317 7 .0

HR6 0.1224 -0 .0 5 7 9 0 .0 7 0 0 7.0

ANISOTROPIC TEMPERATURE FACTORS*ATOM 01X £ 2 2 $33 |Si2 ^ 13 ^23

Fe 0 .0 0 3 5 0 .0 0 3 5 0 .0 0 4 6(3 ) 0 .0 0 .0 0 .0

I 0 .0 0 5 3(1 ) 0.0059(1) 0.0048(1) 0 .0 0 0 3(1) 0 .0 0 .0

*EXP-pSxih2 + fippk2 + ^33 jIs + 2(j3iahk + + ^23^J&)1*

TABLE I-II

RIGID-BODY RING PARAMETERS FOR THE FeIs(CNCsH4CH3 ) 4 MOLECULE

20

RING ORIGIN x 0.281)0 (6 )(Fractional CellCoordinates) y -0.0231(6)

z 0.071)0(3)

RING ORIENTATION Phi 2 .2 8 7(7 )(in Radians)

Theta -0.176(6)Rho 2.884(6)

OVERALL GROUP B 0.0

TABLE I-III

INTRAMOLECULAR BOND LENGTHS AND BOND ANGLES

FOR FeI2 (CNC6H4CH3 ) 4

22

BOND LENGTHS

Fe-I 2 .6 3 2(3 )8

Fe-Cl i.y57(i7)8Cl-N 1 .061((23)KN-CR1 1 .3 7 5(1 7 )8

C2-CR1* 1 .513(2 1 )8

BOND ANGLES

X-Fe-Cl 9 h .5(5)°Fe-Cl-N 1 7 8(2 )°C1-N-CR1 1 7 1(2 )°CR3-CRl*-C2 1 2 1(1 )°N-CR1-CR2 1 21(1 )°

TABLE I-IV

FeI2 (CNC6H4CH3 ) 4

STRUCTURE FACTOR TABLE (CALCULATED AND OBSERVED STRUCTURE FACTORS

ARE TEN TIMES ACTUAL VALUES)

2k

O Q 4 0 0 00 ft 111 0 I 1 ft ft

0*4 491 ft U100ft1411

*3* ft 91 lift* !*■•

* 4* 1 * ** II« 11

9*7 ■ 4f lib Jit »*f

9 1 9 4 9 II * U 0 ft

44fe14133*I**1*1*

90* • It J«« I7Q

17 IB

» 9J 1 J *« IIJ 11

III343JIBtot3J1

• 71 tfef D O 1)3 Tftft

« ) llv* * tr** • m* I* D ) 4 IJ ftffe

191«)«It)110**•

10 10 1 0 IO1 o1 0 *

1 ft II 1 0 1) 1 O |4 1 1 * 1 ft

41ft9011*4!«■Ill)1)44

Bftl11*3911*1

ISJIIftlft

10 0 10 ft10 1311 1 11 J 11 9

*f 1 I/ft 914 3 TftM OJ«*

*

a tft 4 0 00 ft 4 13t 1

II)littft)3)000ftJftft

10*■atmtitft«Z•ift

J IS• f• 4 « 0• II• 1

iat«*J4*19190/■ft)

!••100J«*ISOfell37*

9 1 *ft 9 3 J*l s a 47) b 7 13ft9 * 1*7 S 11 I**

*49 I M 4 J* 10* 1)3 1*9

1ft 1 0 IB 1 0IO10* i b )11 Jftl 11 1 194 0 1 1 ft** 019 * J 111 413 9 1 I M 17) Jo1 1 1* 1 1) »*V II II 19ft 1 i *01 90* 9 9 4*3 •J* • o m ftBI 11I I J

1 1 **)f«44

3*1*•«

II 11 It ft

1 11 • 99

7 ) 4)1n o

i ntftO 9 7

* •ft«J390

SB*111

a ft 1)7 a n t *

3*0•ft

11 11I f )

• a **91««a

• Ift3*1

ia i«* * i

/ft*34ft

7 11 7 t>

i dM l

n oTft* ft II

9 1 1T9J ■ «•

Jl 3 Iftj

« 17 *43r i in

M *lift

V'*lli i n n * 31) I* > 390 7 I* 1** i j) a e Iftl) |*B4 7 1 1*4 **J 11

i l l ) i n 330 n * If* * S B 10*7 IBJJ • it 993 St 0 / S Jft* 4)1 111 1 10 ll* •ft* 14 ft .194 ft * 399 IV* r i fe 17 •a r 7 I Jftft JJ7 11l i f t ii* 1*1 ft J 1 1*/ • ft 1** 1 9* 7 J IB* IBl 1 ft It) III 111 4 4 1 ft • J *

101IftM!*•

l«0I BMIBB

0 9 0 f ft *

III1*1994

■ 4) • 1 * 1

4)7Jftft3ft*

*71JJ4M l

7 B 1 7 / ft

bftl*173J7

9b)JJOlas

7 11 301• a n o• j io r

10* 10 II IJ J

11111 L

1 1 10 1*1 191 ft II 3*4 ft 9 4*7 Jit 7 II 390 tftft a n ifet 1 ft) t L1 1 1 4 M O l*ft 0 1) JJf * / 199 1*4 1 13 lift !•■ ft If 101 317 II• 1 lit 111 o La IftJ ft > 394 140 ft 0 fftftft 103* ft 1 It* 1«t ll1 * 11 TO 1 ft** 1 i 710 * II 1*0 17* 4 It 4*3 *1 7 * J n o 1J4 II1 * 1 111 9*1 | 4 KOI • 19 IB 1 1 3ft 3 0 11*7 lift 4 9 101 119 111 * T *11 *13 1 0 lt/9 Ift 9 ion 1070 ft I JJft j j) ft 7 tfel 301 111 4 9 Tt* 13* 1 ft 1ft I IB 1 7* 13 ft 3 n o 319 * 1 h i 199 Ll1 * 11 41ft 44* 1 10 300 Ift 6 131 *7 ft 9* j*p 3*9 ft >1 19* 101 1 11 * 10 a n IB* 1 14 tlb 19 ft 190 397 ft r tftJ 134 10 0 ««• • 40 J*1 1 1 10) 101 a i aoa 10 13 i n 339 * * 101 17ft 10 13 J04 T9) 111 0 4 H J 331 a j *a* II 1 jaz Iftl i 11 10* 1*9 II 1 til 1)4 111 0 * 141ft 141* a s •SI II J JJJ J* 1 ft D It* Iff II J 19) 1*3 III a io *** 311 a r 934 II 9 JJO M I 10 0 910 900 II 9 17J 14ft 111 0 1* M « 1*1 t * ftftft II 7 (ft) 1«3 10 1 190 1*0 ll T |feb 1 *0 111 ft » *«r • 13 ) ii *91 11 « 1*9 170 io a 177 lift If 0 4*4 *ei 111 4 1 i*r *•3 a n 1*3 11 11 Iftt lot 10 11 379 1*7 13 1 19* Its 1 1i * ft 141 111 t 19 t J7 TO It 0 J»9 430 11 i 10* 3*4 13 9 I7B 194 Iti a It lie 113 1 3 T 14 it a 1)1 *3 11 3 111 333 14 ft Iff 341 11i * i) i n lift J 1 1*19 It 4 ■ 0* 1*4 II T 1*1 31* ft 1 973 lift 11* * 1 0 io* i n 1 ft Of It • 1*1 Oft 11 * IB* tao 0 J *11 Ift9 IIl i t 1*1 IV) 3 10 1ft It 13 113 1)9 17 0 943 • ft* ft 9 ft* I 444 II1 * itto lit! J It 19* 13 I IIJ 3*9 13 1 Ifet 1*9 ft 7 >93 940 It1 1 «** «•* J 1* 103 IJ J 1 BO let 13 a 137 147 ft • fit 134 II1 ft J *01 4*0 4 1 ■ 9ft 13 t 1 7* L 44 13 fl 3 10 119 ft II IB* 3)3 II1 0 ft •ft! act 4 3 941 19 7 1*1 ft** 17 1 17 J 1 *r o 13 lei 1*9 I)1 ft 1 *01 *)) • 9 ISJft 14 0 47| tat 1* 0 J97 JSB i a i d 1*0 II1 ft ft I M JIT 4 r 4*0 • 1 ft 44 ■at B 1 9TJ 930 1 a BB7 *00 ia1 * II ■at 31* 4 • 19* ft 3 *41 «io ft 3 *4* •b* a i * j) *** ia1 0 1) Ifti ISO 4 I I J90 0 9 • II M l * 9 91B 974 3 3 149 J«* ia1 ft J 1*0 I** 4 II 3*0 0 1 JOT • 01 0 7 *** 949 C 9 IVt 3*1 ia1 * ft iet« *4 4 4 19 101 0 » 919 919 0 * U 9 ftft r r j m JBft it1 ft 0 lai *a 9 4 tft* ft 19 31 7 tl 0 0 11 J4fe Jl* a * tea JOB ia1 1 0 1 *•4 *•1 9 ft I47B 1 4 314 BBft 0 13 31* Iftl 3 11 lift Ift* it1 10 J JJO n r 9 10 113 1 0 1 Iftt 1 too 0 IB 3 JO lift t 13 170 I4t it1 10 ft 111 lit • 1 14) 3 1 431 430 i a tie tftft a t ibb BIS it1 io i tftft lift O ft til r 3 •17 094 i • IHI itn 3 • r«s 7ft 1 it1 10 ft 1*0 141 0 9 311 a * 491 490 i * l3*e lair 1 O i l * • 1 it1 i o n 111 lOe o r 410 a 7 919 4 ft* 3 1 • if *09 • 1 *71 90J it1 io tl to* l’» a * 9)9 a • 441 *•1 a 3 9*9 ftftft • 3 3*fe 431 iti ii * 111 141 ft ii JO) a u JTft J*S t B 9*1 94* 4 * 91) 490 tti n ft lit *«T 0 *3 319 > l> 1** a»T a a JJ1 311 * 7 411 Jtl itI I I • 111 10* ) t M e a ib 310 ifti a j 1*1 jftt 4 * 131 3*3 itI it J a n 3*4 7 ft 199 a t too eto t it tftft 310 9 • M o 931 itI 11 3 tit 34J 7 a 1197 j * til 1 73 a n 111 19* 9 1« 131 IJJ ia1 1* B i n 3*1 a i I M j « IJftft 1J1 7 j ■ *43 J*J • 1 379 403 ia1 11 7 D O » 4 0 J 944 J 10 Iftft tot i • 1319 1)74 a 3 sia 43* ia1 11 4 )•! 1*1 0 9 *33 4 t •»■ *03 3 10 Ilf Iftft • 9 T44 130 ia1 11 II ■ 1* 1** a r ITS • 3 tea 3)0 3 1* 303 ITT ft 7 | oi tftft IT1 IJ ft 111 4«2 • * IIJ • » 9*0 ftftft * i JOB 39* • 1 303 tit 1)1 14 | lift TOO a 11 39* 4 1 499 • 90 4 J 7 79 T9* ft II 139 TO) U1 14 J lift Ift* ft 13 tft) • ft J** Jftl * t *3* *19 t r id* *«» tl1 1* ft aoa |TB * a 17* * II tst Jl C 4 1 JTJ 341 1 * 13* •ft It1 0 4 *41 ill * • •S9 4 13 ait 109 • * *91 *09 7 ft 9*4 ft«* If1 0 f t ft) 111 * o lift 9 I tit 1*3 4 11 34* t*J G 1 1*4 Iftl IT1 O I) • 9) a«i IO | Jftl t ft 1104 IttT 9 3 141 1*4 ■ J J M 1*9 111 9 1*1) ♦ *lt 10 3 303 t I* lift tat b * i n 10 4 a s 1*7 aoj Itl i f t TOO t z* IQ 9 40« 0 1 tft) 99* ft 3 •so TOO B 7 1*3 100 ITa i **J 90ft 1ft 7 *11 ft J • 19 90* * 1 |b* 3 tft * 4 ft* lift 1)t ft 1)0 719 10 ft III o e rot 717 a s *13 401 ft • 910 BIO Iti M •01 BJI 10 II 314 « r 494 419 * 7 901 ft) J 10 1 J17 130 fta i) III 39* 11 4 171 * * a n 393 • ft IB* 394 IO ft t)« J U 19■ 1 19 It* 133 II 0 •a* 0 11 n o 319 ft 11 tft! IIJ it i a«c Iftft 13i ) * *9ft 471 It 1 31* ft 13 3*9 tfa 0 13 1 19 1* * io ii ia i 1)0 1)■ i f 14ft 19ft 1* 3 IJ* T ft 1)07 ft* 7 7 ft • 70 BTC II • «17 4*1 Ui ) ll lot Tift It 9 tar ft 1 400 *40 ■ j • Tft * BO It l Iftl 1*1 13* J a m i tore 13 * 109 ft J Ml •a* ft 3 107 J 10 u * a«t ati 3i i ft *•* M l 1 > 3 tl) ft 9 *11 3*0 ft • *341 **7 ft 0 1471 1074 13i j * VI ft * M 13 a •ft* ft 7 410 391 ft 1 t/T 190 ft it n o lit 1)a a ft *■9 141 14 1 1 Oft ft « 31* JQI ft 9 f M III i i i n 930 13a a n 191 401 1* J 14ft • II a «i t*0 0 l| 137 too 1 3 31/ 314 13■ i) 114 1J9 0 ft 149ft ■ 13 in 199 * a 1*1 tfel I B M l *17 I Ja ift lift III ft a Oft ft ft it* i as • • ft Ji ■ 40 1 7 TftJ 134 1 11 * 0 III! t i n o * 9*1 * ft 147 Til 10 1 3*r 344 1 • Tfeft )•• IJ1 * 3 f » 301 « • 1*1 I* 1 J9t Jl* l o J aoa J M 1 ii tr* 1 H 11 4 ar* 11* ft B 4ftt 1ft 3 100 3J3 10 9 139 193 t ft Lbio 1000 t Ja * ■ j* i Jftft ft ia M T 10 B I M too 11 • *39 *14 t 4 III l*« 1 J1 * 13 raa 1)9 O 10 III 10 7 «J0 a>« It 1 •a* I M 7 B i t * 1*7 11■ ft 1 fti* 41) t i M l 1ft ft 17* aao 11 3 14* 19* t It *14 4*4 111 ft J *19 *19 1 9 *40 Ift II 1*9 193 ■ a 9 119 TtQ 3 1 091 ato 11 ft ft tft *00 1 7 • ■7 II t J M JOt it r !•• 1*1 J J tl* 30* 1 1a ft ) *14 410 1 « 194 II * IS* 100 ta n 17* 139 3 9 *17 M * 11a o * act 103 1 It 10t 11 * 940 937 i j • 319 4ft 1 3 1 Jftft 319 13a o n at* 110 L 1) I M 13 1 IftO 141 0 0 1993 13*4 J ft 131 Iftt 13i t ii H i aia 1 19 ■ b* It 1 Oil too 0 * f 74 139 1 11 1*3 IB) I*a is 10ft if* a o 1094 13 0 M l •at 0 0 III 3*1 J U 141 1*0 1*t a t ii* lift t t I M J4 1 313 194 0 It

1 14*9 944 4 0 *3* Itt 1*

■ 4 • 399 310 t 4 * JO 1* s ■ !• IB3 411 9 71 a IT M b )«4 41 ft 0 191 ISO 3 9 40* 9 ft IftTT 1730 1 3 •9* • It 9 1 M t H I l»* * ft 141 341 a io to* * ft 1*3 *0 | • 940 9fe* 9 3 34* 349 tti a ii *«! 909 a ia art 0 ft 3*r 3)4 1 7 *01 JTJ 9 4 3*1 Jl 4 1*a ) I Ill • 00 j t ♦ Ift 0 11 I M • It I * 301 19* S 7 f J* tat Jfta r a • ■I 01* j a 734 1 I 0*9 70S 1 11 391 304 9 ft tit aia 1*i ) » 141 411 3 9 9*7 1 J •40 ■ft* 1 1J tto aia 9 II l»* n t 1*t i t 3*1 1*1 3 7 • 10 1 B 434 37* ■ * I3V1 i J*t B ft 49) fttt I*l i f t 4ft* JftJ a B 441 1 7 • 79 430 ( * It* at 9 4 |»r i d *a ) il i n 130 3 II 9*3 1 • 4SJ 44* I ft 13* 190 a ft I M isj 1*a ) is IT* • 10 a *3 14 0 1 II too tft* a ia

3 |4*4 *ir * it to* n t 1*

« 1 IB Iftl 111 3 IB 1*1 1 13 1 T9 1*3 473 *i* r i tst tr* 141 * 0 14*0 1*04 « a 140 I a S3 11 • J 3 3*3 340 f a ft 3 143 1*1 0 * 1*1 *•3 * » *ft a * 3*9 M O 3 ft ftftft 4*4 7 9 1*4 II) 14l i f t 111 111 • ia 4*4 3 B lit lit J t IT* JJO T 7 14ft 1)4 t*a • it *«r 494 9 1 oat i a it 9*4 97* J ft 3*1 3*4 T * tftft lift) ft 1 4ft t 4 D 9 3 411 j i tftft It) 3 tl 3*1 1*7 7 11 111 ItJa * 9 4ft9 4ft 9 4 *10 j j •ft* Oft * ft 0 IL*7 III! • 0 37* 4*3

139IS O71*

141AIMl l«U lii n Mr * i i moi« ij i pi n141»J«l «1*1non111j r *M ltN1 J »111ffelIIJ1143LO101iroifl1«4»*) 111 I 14 4 M 1*9 LftS**r10*noi di t *1)0 i ■«i * i4 M111»9 J1*4I I *I I )1*9• tl t** Jtl 111 I I ) 1*4 1 *0 11* IBS• 7» I t ) I I * »)l 110 101 100

114 11* 19Btoei f*JO*i l li nte i14*111100MOtiei« ii df i rIJI 1*1 i l l 44*i«o

i « » » 10* 10 r 1 1 4 1 * 4 ) 4 >

l ie114• ri•k«

10i f i40B1*11*11ST14)roe)•**)*1*01*0I I I

!* •n oi nI JO 4 9 * 111 <«4 l O I 1)4 J«* l«B lb* • a r i * i n o14*1 1 914)*44) J *I)*

I t )*U

n o14*1*4Im10*o ni * tn o10*1*4i t *10)

1*)116I* )01)1*0>**)*»1*1I I )i n*o)4*

101 4 ) 0 1 4 4 1*1 (IB I )J I M 104 4 / au *

141IMi r a1*4J fttH iH I

4 1 4n o i m1 *4JM 14 0 1*1

0 0 0 I M f « * I T * ) J 4 ) J b M l *11 K M 14ft l ) J I t *104 4 0 1 IIJ IM *01 1*9 1*1 n oM l

4 ) 010911*111I**i j )400 1 1 J l i f t 41* I OB 1*0 1)0 n»

DISCUSSION

In Figure 1-3) the displacement of the Isocyanide ligands from the equatorial (xy) plane can be seen. Due to the location of the iron and iodine atoms on the II crystallographic axis, alternate ligands lie below and above the equatorial plane. If only the imme­diate iron coordination sphere, which contains the two I atoms and the C-N-C segments is examined, the molecular symmetry is Dg^-

When the phenyl rings are considered, however, the molecular symmetry is lowered to S4, the symmetry imposed by the crystallogra- phlc space group. The ring carbons (CR1) to which each nitrogen is attached lie 0 .^ 5 fi from the equatorial plane, and the vectors normal

to the planes of the phenyl rings are at 17° with respect to the Fe-I bond vectors. 16 This tilt of the phenyl rings with respect to the equatorial plane destroys any mirror symmetry which the isolated mole­cule might possess.

A [100] packing projection (viewed down the x axis) is presented in Figure 1-4. If the projection is viewed down the z axis, the [001] projection (Figure 1~5) results. The iron and iodine atoms occur on the II axes, and the four-fold screw axes pass through the phenyl ring stacks. The methyl and isocyanide ligands are stacked in neat diagonal rows as seen in Figure I-5. As a result of this type of cell packing, unobstructed channels of approximately 3S in diameter parallel the z axis. While numerous small linear molecules (e.£. Ns , 02, or C02) could be trapped within these channels, a final Fourier

difference map based on the coordinates for all of the atoms within

25

26

the asymmetric unit (excluding the hydrogen atoms of the methyl group) revealed no electron density above background, thus establishing that there were no trapped molecules within the crystal studied.

The Fe-I bond distance of 2 . 652( 5 )8. compares favorably with the values of 2 -65 (l )JS reported by Andrianov and Struchkov in their series of formally six coordinate lron(ll) compounds based on the

two Isomers of (Tr-C5H5)Fe[P(0CeH5)3]2I and (TT-C3H5)Fe[p(CeH5)3 ](CO)21 . 1 7 * 18

However, these bond lengths are all significantly shorter than the

2.75(1)$ bond distance reported by Mlnasyants and Struchkov for (TT— C3H5 )Fe(CO)3 I . 19 The authors propose that for (TT-C3H5)Fe£p(CeHs)3]- (CO)2I, the replacement of one of the carbonyls with a triphenyl- phosphine group with less TT-acid character or a smaller trans effect results in the decrease in the Fe-I bond distance.

For comparison with the Fe-C bond distance of 1.92(2)$ and the C-N bond distance of 1.06(2)$ there are four different iron(Il) compounds reported in the literature. Enemark, and coworkers, in a

communication on [Fe(CNCH3 )s*CH3NH2 ][PFa] 2 reported average distances for the four nonchelating isocyanide ligands as Fe-C, 1.86(2)$; and C-N, 1.15(2) $ . 30 These latter bond lengths are similar to the values determined in 19^5 by Powell and Bartindale for Fe(CNCH3) 3C12 *3H^0:Fe-C, 1.85$; and C-N, 1,18$.21 Wilford, et jil., studied the crystal structure of Fe(CN)2(CNCH3 )4 *hCHCl3 . 22 Due to extensive intermolecular interaction, they were unable to discern any significant variation in bond lengths from those reported earlier for the Fe(CNCH3)62~ group.

Christoph and Goedken studied the complex anion Fe(CN)4[CeH4(NH)2]2- by X-ray diffractometer methods. 23 They report four different values

for the Fe-C bond distances ranging from 1 .9 1 7(3 )$ to 1.9^2(3)$ with a

27

mean value of I.9 2 7 8. There Is no significant variation in the values

reported above and those in the molecule studied here.Within the para-tolyl group, the N-CR1 bond length is

1 .3 8 (2 )8 , not significantly different from that cited by Ferguson for a carbon sp^-nltrogen ap bond length of 1.5 6 8 .24 The methyl group (C2) is 1.51(2)8 from the para-carbon (CR4). This bond length com­pares favorably with 1 .52(1 )8 value reported for toluene55 and with1 .50(1 )8 value reported for xylene. 26

The Co-I bond distance of 2.692 (6 )8 reported by Gilmore, et al., for the Col(CNC6H4CH3 ) 4 analog1 of Fel(CNC6H4CH3 ) 4 is signi­ficantly longer than the Fe-I bond length of 2 .632(3 )8 , but the Co-C bond length of 1.81(4)8 is only slightly shorter than the Fe-C bond distance of 1 .9 6(2)8 . The C-N bond length of 1.14(4)8 in the Co com­pound is not significantly different from the value of 1 .0 6 (2 )8 found in the Fe analog. The fact that the metal-iodine bond distance de­creases significantly on going from a d7 to a de central metal ion offers proof for Maher’s original assignment of the molecular orbital energy levels. 2 >3 A schematic molecular orbital diagram is illustrated (Figure 1-6) for the FeI£(CNC6H 4CH3 ) 4 molecule, assuming a coor­dination symmetry about Fe. Due to the anti-bonding nature of theAj.* (d 4) molecular orbital for the dQ metal compound, addition of zone electron to this unoccupied orbital will lengthen the metal-iodine bond. This increase in metal-iodine bond distance occurs in CoIs(CNC6H4CH3)4, the d7 analog of FeI£(CNC3H4CH3)4.

Mossbauer data were generously supplied by Good for the EeI£(CNCeH4CH3 ) 4 . 27 The spectrum was obtained at 77°K. The isomer shift was found to be -W .39 mm/sec and the quadrupole splitting

28parameter was 1.73 mm/sec. Both parameters were strongly Indicativeof substantial "back bonding" occurring between the CNC^H4CH3 ligandand the iron. The filled TT type orbitals of the Iron, d and d ,

r * xz yz*are available to Interact with the tf* antibonding orbitals of the isocyano groups. The TT* isocyano orbitals will have some overlap with the TT orbitals on the benzene rings since the displacement below the equatorial plane and the tilt of the rings is small. In addition, the d ^ metal orbital is available to Interact with the TT* isocyano orbitals contained in the xy plane. Figure 1-7 illustrates this "back bonding".

FIGURE 1-3

ORTEP STEREOSCOPIC DRAWING OF THE FeI2 (CNCeH4CH3 ) 4 MOLECULE

(WITH 50$ PROBABILITY ELLIPSOIDS)

31

FIGURE 1-k

[100] PLANAR PROJECTION OF THE UNIT CELL OF FeI2(CNCQH4CH3 ) 4

32

►5«,

FIGURE 1-5

[001] PLANAR PROJECTION OF THE UNIT CELL OF FeIs(CNC0H4CH3 ) 4

3h

FIGURE 1-6

SCHEMATIC MOLECULAR ORBITAL DIAGRAM FOR Dgd MODEL OF FeIa(CNCsH4.CH3 ) 4

3 6

Fe(ll)ORBITALS

MOLECULARORBITALS

LIGANDORBITALS

fcp (Bg ,E)

^3 (Aj)

UNFILLED

(2A^ >Ag t B^ >2Bg,3E)

TT*(CNAr)i Ag,

BI,B2*2E)

3d (a1 ,b1!

V (dxa-ya)

b2 .e ) _ l i 11___ B (a ,d )ti t l y t l a d )tl t l (Aj.Bg)

tl B, fd ) ------ 1 ' xy-Jr a(CNAr)7T— < V Bi ’tl E)

FILLED(BONDING)(2Ax >2B2,

E)

FIGURE 1-7

METAL-LIGAND TT INTERACTIONS IN Fel2(CNC6H4CH3)4

REFERENCES1. J, P. Maher, Chem. Comm,. (1967)6 32.2. J. P. Maher, J. Chem. Soc. (A), (1968)2 9 1 8.3* C. J, Gilmore, S. F, Watkins, and P. Woodward, J. Chem. Soc. (A),

(1969)2833.h. International Tables for X-Ray Crystallography. Vol. X, Interna­

tional Union of Crystallography, Birmingham, England, 2nd ed„, I9 6 5.5. S. F. Watklns,MORIENT, A Fortran IV Computer Program for Orienta­

tion on the Enraf Nonius PAD-3 Diffractometer,1* Louisiana State University at Baton Rouge (1969).

6 . J. M. Stewart, "XRAY *67, A Fortran Computer Program System for X-Ray Crystallography," University of Maryland (1967).

7* S. F. Watkins, "DIFSET, A Fortran IV Computer Program for Gener­ating Settings and Control Cards for the Enraf Nonius PAD-3 Dif­fractometer," Louisiana State University at Baton Rouge (1970).

8. S. F. Watkins, "DIFDAT, A Fortran IV Computer Program for Reducing Data Collected on the Enraf Nonius PAD-3 Diffractometer," Louisi­ana State University at Baton Rouge (1970).

9- J. J. Bourg, "REDUCELL, A Fortran IV Computer Program for Calculat­ing the Reduced Cell," Louisiana State University at Baton Rouge

(1971).10. H, P. Hanson, F. Herman, J. D. Lea*, and S. Sklllman, Acta

Crystallogr., 17( 196^) lQlj-0.

11. S. F. Watkins, "RBANG, A Computer Program for the Calculation of Rigid-Body Angles," Ph.D. Dissertation (Appendix i), University of

Wisconsin (I967)•

39

40

12. W. R. Busing, K. 0. Martin, and H. A. Levy, "ORFLS, A Fortran Crystallographlc Least-Squares Program," ORNL-TM-305. Oak Ridge National Laboratory (1962}j "ORFLSD, A Fortran Crystallographlc Least-Squares Program Adaptation of ORFLS for Rlgld-Body Refinement," University of Wisconsin (1969)*

13. W. C. Hamilton, Acta Crvstallogr.. 18(1969)502.

14. H. A. Levy, Acta Crvstallogr.. 2( *956)679.15. C. K. Johnson, "ORTEP, A Fortran Thermal-Ellipsoid Plot Program for

Crystal Structure Illustrations," ORNL-3794, Oak Ridge National

Laboratory (1965).16. J. J. Bourg, "PLANET, A Fortran XV Computer Program for Calculating

Least Squares Planes," Louisiana State University at Baton Rouge (1971).17* V. G. Andrianov and Yu. T. Struchkov, Zh. Strukt. Khim., £(*968)240;

and 2(1968) 503.18. M. Kh. Minasyants, V. G. Andrianov, and Yu. T. Struchkov, Zh. Strukt.

Khim.. 9(1968)1055.19. M. Kh. Minasyants and Yu. T. Struchkov, Zh. Strukt. Khim., £(1968)665.20. J. Miller, A. L. Balch, and J. H. Enemark, J. Amer. Chem. Soc.,

22(1971)4613.21. H. M. Powell and G. W. R. Bartindale, J. Chem. Soc.. (1945)799*22. J. B. Wilford, N. 0. Smith, and H. M. Powell, J. Chem. Soc. (A) ,

(1968)1544.23. G. G. Christoph and V. L. Goedken, J. Amer. Chem. Soc., 95( 1973)3869.24. L. N. Ferguson, The Modern Structural Theory of Organic Chemistry.

Prentice-Ha11, Inc., Englewoods Cliffs, New Jersey, 1963* P. 35> 59*25. F. A. Fadel, Ann. Revs. Phys. Chem.. 4(1953)236.

kl

2 6 . C. Sheringer, Acta Crystallogr.* 16 (19 65 )5U6.

27. M. L. Good, private comminication, Louisiana State University at New Orleans (1971).

XX

TRANS - HYDRID OCARBONYLTRIS (TRIP HENY LP HOSPHINE ) COBALT (l)

k2

INTRODUCTION

Ewens and Lister reported the first molecular structures of two transition metal hydrides In 1939*1 Using electron diffraction data from gaseouB CoH(CO)4 and FeHs(CO)4, they concluded that both central metal atoms were surrounded by a tetrahedral arrangement of carbon atoms. As the hydrogen atom did not appear to be exerting any stereochemical influence, they proposed that the hydrogen must be at­tached to an oxygen. This refuted the theory offered earlier by Hieber, who had been the first to synthesize both FeH2(CO)4,a and CoH(CO)4.3 In 1937> he had theorized that the hydrogen atom was burled within the metal orbitals and thus the CoH and FeH2 configura­tions were "pseudo-atoms" and the two compounds were "pseudo-nickel carbonyls".3 Hieber reiterated his theory in I9lf2 ,4 In 1952, how­ever, Hieber reversed his stand and suggested that the hydrogen was indeed bonded to the carbonyl oxygen.3 He proposed that the 0-H bond was at a 90° angle with the M-C-0 axis, thus keeping the hydrogen within the electron sphere defined by the tetrahedral carbonyl con­figuration.

The controversy continued. Studies on transition metal hydride complexes were reported that utilized lr, nmr, electron dif­fraction, and LCAO techniques, as reported in numerous reviews.6*7 >a In i960, Owston, e t al., reported the first X-ray diffraction study of a transition metal hydride.9 Though the hydrogen atom was not ob­served in PtHBr[p(0^5)3]2, there was an apparently vacant site available trans to the bromine atom in a slightly distorted square planar configuration. Laplaca and Ibers were the first to locate the

43

hydrogen atom In their 1963 X-ray diffraction study of RhH(CO)- [FfCeHgJaJa, reporting a Rh-H distance of 1.72(15)S. 10 The first neutron diffraction Investigation of a hydride complex was reported by Abrahams, et al., In 19614- for KaRelfe. 11 They cited an average Re-H internuclear distance of 1.68(l)fi for the tri-capped trigonal prismatic configuration of ReHg 2".

To date, additional X-ray studies of transition metal hy­drides, with the apparent exception of such structures as RhH[p(cQH5)3]4 reported by Baker and Pauling,12 offer additional evidence for the stereochemical Influence exerted by a hydride ligand. In RhH£p(CsH5)3 ]4, the four phosphorous atoms are arranged in a regular tetrahedral configuration around the rhodium, and the proposed hydrogen was not observed. Thus the presence of the hydride in this compound does not appear to influence significantly the geometry of this compound (see Discussion). Thus, the stereochemical role of the hydride ligand was not fully characterized. In an attempt to further understand the stereochemical influence of the hydride moiety, the single crystal X-ray diffraction analysis of C o H ( C O ) w a s undertaken.

PREPARATION

CoH(CO)tP(C6H5)3]3> a five coordinate cobalt(l) complex, has been reported to have been prepared in numerous ways, Misono, et al., bubbled carbon monoxide through a solution of CoH(Ns)[P(CeH5)333 and also reacted formaldehyde with CoH(Ns)^(CaH5)3]3 , both methods yielding hydridocarbonyltris(triphenylphosphine)cobalt(l).13 Otsuka and Rossi reacted TT-cyclo-octenyl-TT-cyclo-octa-1,, 5-dienecobalt, Co(CaHa3)(CaHig), with triphenylphosphine in toluene to get the same product,14

Tupper, who generously provided the Co-H crystals used in this study, synthesized CoH(CO)[P(C0H5)3]3 in the following manner.15 [Co(H20)4]C1£*2H^0 was heated with an excess of triphenylphosphine in ethanol to produce blue crystals of CoCl£[p(c6H5)3]2, The blue crystals were mixed with an excess of NaBH4 and P(G6H5)3 in ethanol and allowed to react at 0° C for 2 hours. Yellow crystals of CoHa- [p(CeH5)3]3 which were produced were then subjected to bubbling carbon monoxide in toluene at room temperature. To the resulting orange solution hexane was added and this was stored in a freezer.Orange crystals of CoH(C0)[P(CeHg)3]3 were formed slowly. All pre­parations were carried out in an argon atmosphere using deoxygenated solvents. The cobalt monohydride was stable in air, but unstable in solution, thus frustrating any attempts at recrystallization.

After numerous attempts, crystals large enough for single crystal Xrray diffraction studies were obtained from the reaction

mixture. This X-ray study was to be preliminary to a neutron dif­fraction analysis, but as of this time, It has not been possible to

1*5

kS

prepare crystals large enough for neutron use. In addition to Tupper's analysis of the compound, a high field nmr spectrum was obtained.The quartet centered at approximately 23 t was observed in a time averaged 100 MHz spectrum with P-H coupling constant of 50 Hz. These values duplicated those reported by Otsuka and Rossi.1,4

EXPERIMENTAL

Determinations of the preliminary cell constants, crystal orientation, and space group were accomplished using an Enraf Nonius 601 X-ray generator and compatible Weissenberg and Buerger precession cameras. Both molybdenum and copper normal focus tubes were used with wavelengths ® 0.710?S and 1.54188, respectively.

Numerous crystals were studied due to problems such as twinning and decomposition. It was finally concluded that the crys­tals, though air stable, were moisture sensitive. Prolonged exposure in our air-conditioned laboratory, which does not have controlled humidity, resulted in a "sugar coated" appearance on the surface of the crystals. Various methods of isolating the crystals from the air were attempted. The most satisfactory treatment proved to be coating a crystal with numerous thin layers of Duco cement thinned with amyl acetate. The crystal finally chosen and treated in the preceding manner proved quite stable over the seven-month span required to col­lect diffractometer data with no visible deterioration in physical appearance nor any significant statistical fluctuations in the moni­tored standard reflections.

The data crystal was mounted with the b-axls colinear with the diffractometer phi axis. The dimensions of this crystal, which had been cleaved from a larger needle, were approximately 0.16 x 0.20 0.^6 mm, measured with the aid of a calibrated binocular microscope reticule. The faces of this transparent orange needle belong to the forms [lOO], {001}, and {110}.

48

Orientation on the Enraf Nonius FAD-3 Diffractometer was facilitated with the use of ORIENT, a crystal orientation program.le Forty-three well centered reflections were refined In 29 using XRAY '67 to obtain final cell parameters. 17 Data collection was begun using control cards generated by DIFSET. 18 The initial X-ray tube was a molybdenum fine focus tube, but after 370 reflections had been collected, the tube failed. It was replaced by a normal focusmolybdenum tube and data collection reinitiated.

When data collection was resumed at reflection 300, the original conditions were altered. The theta limit was lowered from 25° to 20°, the optimization was deleted and all reflections collected without attenuators, and backlash corrections were removed from theta and chi axes and were retained only in the sensitive phi axis. Thetheta scan rate was one-half degree per minute, with initial andfinal background counts of 10.00 seconds apiece. The scan range in two theta, SR, was calculated as follows:

SR = 1.800 + 1.000* tan (e).

Three standard reflections,0 -6 0 , -2 -1 -4, and 2 0 -8 , were col­lected after every 97 reflections.

Due to major electronic malfunctions within the control modules, the 4516 reflections were collected using various modifica­tions of the usual methods for data collection on the Enraf Nonius PAD-3. Over 400 reflections were collected and recorded manually; the next 1480 reflections were collected with a continuous Hollerith card-punched data stream and constant monitoring of the settings.The remainder of the reflections were collected under normal

k9

conditions. These Latter reflections, as well as the manually col­lected data punched In a formated data mode, were compatible with the program designed for data reduction, DiFDAT.19 However, before the 11*80 reflections collected with the unusual data stream could be re­duced by DIFDAT, major alterations and additions to the data were necessary.

The data output stream was a continuous repetition of the following format:

... 11 AXXXXX 12 AXXXXX 13 AXXXXX 92 YYYYYY 9 k ZZZZZZ...

Three repeats of this data line comprised the information collected for one reflection. The two digit integers are the addresses of various electronic components: 11 is the theta axis positioner, 12is the chi axis positioner, 13 is the phi axis positioner, 92 is the scalar, and 9^ 1b the timer. In the six digit integers, A designates the rotation rate of the axis motors, XXXXX represents the angular position of the axis in centidegrees, YYYYYY is the integral photon count, and ZZZZZZ records the time in centlseconds.

By a major modification of DIFSET which is contained pri­marily in the subroutine EZEOUT (see Table II-l), the pertinent data were extracted from the data stream, double-checked for compatibility and accuracy, and punched out on Hollerith cards along with the appro­priate values for the hkl Indices, peak theta value, and reflection number in a form compatible with DIFDAT.

In DIFDAT the intensity was reduced by applying an Lp cor­rection, and an estimated standard deviation a(l) calculated by the

formula

50

C represents the Integral photon count for the theta scan (scan) or Initial and final backgrounds (bgi and bg2), and T indicates the time in seconds. If the reduced intensity was greater than 2a(l) the reflection was designated observed. There were initially I782 ob­served reflections. Structure amplitudes Fo were extracted from the observed intensities with standard deviations o(F) estimated by the formula

silI

At this point, the reduced data were ready for use in solving the crystal and molecular structure.

TABLE XI-I

SUBROUTINE EZEOUT

ssjjjsfssfs -K il«? i.sA:;:!!!8*:1** s >i i‘ \in fs sf3 p ?I? S s * ! ! 5 j* p i is I: *-!s ; -j r.-s :* n n :m sS; * i gsg j Ss si? 5: ;?:■*'j;M==iis: :• .*■s i n ~ «e ** h frt- s? - ? \n f a =:s « vzi?i ig&is-::; s*! Is I ! i jM Mi i i 1 i = = isi H fetl!, J |i8i i I 1r i n * r p i-«! Is nil mma i

CRYSTAL DATA

Trans-hydridocarbonyltria(triphenylphosphine)cobalt(i), CoH(CO)[p(C0H5)3]3, crystallizes In the monoclinlc system. The space group is P2j/c (c^, No. 14)20 with cell dimensions a *= 17.072(14)8 ,

b=ll.411(8)8 , c = 25.044(24)8 , and ft ■ 107.41(7)°. The experimental density (D@) was determined by flotation in both organic liquids and concentrated salt solutions. Six different suspension media resulted in = 1.250(5)g/ml. This compared favorably with a calculated den­sity, Dc *■ 1.248g/cm3 , based on four molecules per unit cell and V “ 4655.683 . The crystal is centrosymmetric, and the primitive unit cell and reduced cell are equivalent.

53

SOLUTION OF THE STRUCTURE

A reduced data produced by DIFDAT were loaded onto a disc storage file along with atomic scattering factors calculated by Hanson, et ^l.21 The disc file was compatible with the master crystallographic computing package, XRAY '67.1T Numerous attempts at solving a clas­sical Patterson function map and conpiimentary Harker line peaks at

0 , ^ + 2y, § and Harker section peaks at -2x, |r, ■jf -2z proved fruit­less.

The direct methods approach was attempted next. The reduced data and atomic scattering factors were input into ECALC,22 a program designed to produce normalized structure factors Ej^. The 361 E^^'s with values greater than or equal to 1.68 were selected as input for MULTAN, a direct methods computer program.23 The statistics based on the E^^'s compared favorably with that predicted for a centrosymmetric space group. MULTAN assigned phases for all of the reflections. Four different S2 relationships resulted.24 The set of weighted normalized structure factors with the highest absolute figure of merit (1.457) was chosen as input for an electron density map generated by the FOURR link of XRAY '67.

Examination of the E map revealed the cobalt atom and two of the three phosphorous atoms. The resulting vectors did occur in the Patterson function, but had not been among the many sets previously tried. The atomic coordinates and isotropic temperature factors of the cobalt and two phosphorous atoms were varied for four cycles of diagonal least squares based on the complete set of observed reflec­tions. The resulting R value was These parameters were then

used to generate a Fourier difference synthesis. The third phospho­rous atom was located, and after four cycles of diagonal least squares analysis the R value dropped to 0.367* Various carbon atoms in six of the nine phenyl rings were detected in subsequent difference maps. RBANG, a program originally designed to give the orientation para­meters for a rigid-body, was used to predict the positions of the remaining ring carbon atoms. 25 RBANG required two vectors to define the orientation of the ring, so with only three ring carbons, or two carbons and the attached phosphorous, this condition was met. The calculated positions for the missing carbon atoms were checked on the crystallographlc working model, and added to the parameter list. Carbon-carbon bond distances were taken as 1.397&, and carbon- hydrogen bond distances as l.OOfi.

When the six rings were complete, the full matrix least squares program for molecules containing rigid-body groups, ORFLSD, was used.2® After five cycles the R value was 0 .2^2. The refined parameters were then input into the XRAY '67 master file and an addi­tional difference map generated. The remaining three phenyl rings were extracted from this map. After four cycles of ORFLSD the R value had dropped to 0 .100. At this point, each observed structure factor was weighted according to the reciprocal of its variance:

After four cycles of ORFLSD the parameters converged with a weighted R value (wR) of 0 .0i*6 . The isotropic temperature factors on the co­balt and three phosphorous atoms were converted into the anisotropic

Since the 3 x 3 matrix is symmetric, this reduces to

S .J-S 08 j3n h 2 + j3s>zks + jS33Jta + 2j3j. Vk +2/Sxahj1 + 2/323k£.

Three cycles of ORFLSD reduced wR to 0.045. B's of the ring carbon atoms (which had not been varied prior to this time) were then re­leased. After three cycles the least squares fit converged to wR of

0 .041. The isotropic temperature factors on the carbonyl group were converted into anisotropic temperature factors and varied for three cycles before converging to a wR of 0 .041.

At this point a final Fourier difference map was generated, and the hydride atom was readily discernible as the most intense peak. Due to the size limitation of the XRAY: ,67 atom file, the ring hydrogens had to be deleted to generate this Fourier difference map. The peaks associated with these hydrogens were also visible in the otherwise featureless difference map. After two cycles of ORFLSD, in which the hydride atom was included but not varied, wR converged to 0 .01(0 . A final editing of the reflections occurred at this point, and questionable reflections were deleted, leaving a total of 1900 re­flections. Two final cycles of ORFLSD, in which 163 parameters of a possible 241 were varied. The final R was O.O87, and wR was O.O38 with the error of fit (EOF) equal to 1.66. The maximum shift-to-error ratio in the final cycle was 0.06.

Figure 2-1 contains a labeled ORTEF drawing of CoH(C0)- [P(CeH5)3]3.a7 Figure 2-2 presents a stereoscopic pair of this

molecule. The atomic coordinates and temperature factors are listed In Table II-II for the non-group atoms. Table II-III lists the rigid- body ring parameters, and Table II-IV contains the rigid-body atomic coordinates and temperature factors. In Table II-V the important intramolecular bond lengths and bond angles are presented* Table II-VI lists the observed and calculated structure factors.

FIGURE 2-1

ORTEP DRAWING OF THE CoH(C0)CP(CeHs)g]3 MOLECULE

(RING HYDROGENS ARE OMITTED FOR CLARITY.PHENYL RINGS A, B, C, ARE BONDED TO PI.PHENYL RINGS L, M, N, ARE BONDED TO P2.PHENYL RINGS X, Y, Z, ARE BONDED TO P3 «)

59

FIGURE 2-2

ORTEP STEREOSCOPIC DRAWING OF THE CoH(CO)[P(C6H5)3]3 MOLECULE

TABLE II-II

ATOMIC COORDINATES AND TEMPERATURE FACTORS FOR THE CoH(c)[p(CqH5)333 MOLECULE

ATOMFRACTIONAL CELL COORDINATES

x y zISOTROPIC

TEMPERATURE FACTORS, B

Co 0 .2155(1) 0 .2976(2) 0.1714(1)PI 0.2245(2) 0.2906(4) 0 .2606(1)P2 0 .3218(2) 0.3502(3) 0.1427(1)P5 0 .1192(2 ) 0.1916(4) 0 .1140(1)c 0.1690(9) 0.4304(15) 0 .1545(6 )0 0.1363(7) 0.5237(9) 0 .1440(5)H* 0.2529(75) 0.1860(75) 0 .1792(7 5 )

ANISOTROPIC TEMPERATURE FACTORS**

ATOM 0 n 022 0£3Co 0.00308(11) 0.00522(21) . 0.00129(5)PI 0 .00325(23) 0 .00680(43) 0.00155(9)P2 0 .00379(23) 0 .0047^(46) 0.00154(9)P5 0.00312(22) 0 .00704(48) 0.00145(9)C 0 .0039(10) 0.0114(23) 0.0013(4)0 0.0071(8) 0.0099(15) 0.0038(3)

ATOM 012 012 023

Co 0 .00046(16) 0.00063(5) 0.00032(10)Pi 0.00037(31) 0 .00075(11) 0.00010(19)P2 -0.00004(27) 0.00099(11) -0.00007(16)

*5 0.00039(31) 0.00053(11) 0 .00035(19)c 0.0009(12) 0.0005(5) 0.0009(8)0 0.0031(9) 0 .0020(4) 0.0021(6)

Estimated standard deviation based on five times the maximum standard deviation.**EXP- CjSuh2 + 02242 + fesJfc2 + 2(/S12hk +

TABLE II-III

RIGID BODY RING PARAMETERS FOR THE CoHCCOjtXCsHs^ja MOLECULE

RINGS A, B, AND C ARE BONDED TO Pi;

RINGS L, M, AND N ARE BONDED TO P2;RINGS X, Y, AND Z ARE BONDED TO PJ.

On■F"

ORIGIN

FRACTIONAL CELL COORDINATES ORIENTATION ANGLES (IN RADIANS)

RING X y z Phi Theta Rho 0

A 0.1245(4) 0 .2771(9) 0.2764(3) 0.074(6) -2.752(4) 3.007(5) 0.6060B 0.2800(5) 0 .1685(7) 0.3041(4) 1.391(7) 0 .691(6) -2.275(6) 1.8425C 0.2727(5) 0 .4208(7) 0 .3031(3) 0.700(7) -0.693(5) -0 .665(6) O.7U 3

L 0 .3472(5) 0 .2168(7) 0 .0965(3) 2.588(6) 0.597(5) 2.316(6) 1.5092

M 0 .3194(6) 0.4643(7) 0 .1006(3) -1.225(7) 0 .589(5) 2.357(6) I.6I60

N 0.4217(5) 0.3378(8) 0.1987(3) 0.592(5) 0 .384(5) -1.010(5) 1.0002

X 0.0110(4) 0.2004(10) 0.1173(3) -0.114(7) 0.441(4) 3.097(5) 2.0171Y 0.1002(6) 0 .2566(8) 0.0393(3) 0.894(5) 0 .072(5) 1.154(5) 1.1610Z 0.1367(5) 0 .0520(7) 0 .1138(4). -1.252(27) 1-349(4) -0 .072(27) 0.8759

TABLE II-IV

ATOMIC COORDINATES OF THE MEMBERS OF THE RIGID-BODY RINGS IN THE MOLECULE CoH(CO)[PCCflHsJak.

THE THREE-SYMBOL MNEMONIC FOR EACH ATOM INDICATES(1) THE ATOMIC SYMBOL FOR THE ELEMENT,

(2) THE RING IN WHICH IT OCCURS, AND(3) THE POSITION WITHIN THE RING (l IS THE

POINT OF ATTACHMENT AND b IS THEPARA-POSITION).

67

------- raAmOgAL CELL_COpgj)INATES-------- •ATOM x y z FACTOR, B

CAl 0.1245 0.2771 0.2764 2.8(3)CA2 0.0822 0.1717 0.2608 3-9(3)CA3 0.0048 0.1565 0.2680 5-0(4)CA4 -0.0302 0.21*68 0.2909 4.9(4)CA5 0.0121 0.3522 0.3065 4.4(4)ca6 0.0895 0.3674 O.2992 4.2(4)HA2 0.1073 0.1071 0.2444 6.0HA3 -0.0254 0.0811 0.2569 6.0HA4 -O.O856 O.2359 0.2961 6.0HA 5 -0.0131 0.4168 0.3229 6.0ha6 0.1197 0.4428 0.3104 6.0CBl 0.2801 0.1685 0.3041 2.3(4)CB2 0.2629 0.1388 0.3535 4.1(4)CB3 0.3076 0.0502 0.3878 5.0(4)cb4 0.3695 -0.0087 0.3727 5.5(5)CB5 0.3867 0.0210 0.3233 4-5(4)CB6 0.31420 0.1096 0.2890 2.6(3)HB2 0.2186 0.1810 0.3643 6.0HB3 0.2953 0.0290 0.1*232 6.0HB4 0.1*015 ^0.0721 0.3973 6.0HB5 0.1*310 -0.0212 0.3125 6.0h b6 0.351*3 0.1309 0.2536 6.0ccl 0.2727 0.4208 0.3031 2.8(3)CC2 0.21*37 0.5327 0.2846 3-9(4)CC3 0.2841* 0.6317 0.3124 4-5(4)cck 0.351*0 0.6188 0.3586 4.1(4)CC5 0.3830 0.5069 0.3771 5.2(4)cc6 0.31*24 0.1*079 0.3493 4-9(4)HC2 0.1939 0.5419 0.25I5 6.0HC3 0.2637 0.7118 0.2991 6.0HC4 0.3831 0.6896 0.3784 6.0HC? 0.4329 0.4977 0.4102 6.0h c6 0.3631 0.3278 0.3625 6.0

68

CLl 0 .3t|.T2 0.2168 0.0965 2.0(3)CL2 0.3359 0.0989 0.1073 2.5(3)CL5 0.3^97 0.0122 0.0717 4.5(4)CL 4 0.3750 0.0435 0.0255 5.9(5)CL5 0.3863 0.1614 0.0148 5-8(4)CL6 0.3724 0.2481 0.0503 4.4(4)HL2 0.3178 0.0765 0.1404 6.0HL3 O.3U6 -0.0722 0.0794 6.0hl4 0.3849 -0.0186 o.oool 6.0HL5 0.4044 O.I838 -0.0183 6.0hl6 0.3806 0.3325 0.0426 6.0CMl 0.3195 0.4643 0.1006 1.7(3)CM2 0.3850 0.5431 0.1116 4.1(4)CM3 0.3806 0.6409 0.0773 6.4(5)cm4 0.3106 0.6599 0.0320 5*3(4)CM5 0.2450 0.5812 0.0210 4.3(4)cm6 0.2495 0.4833 0.0553 3.2(4)HM2 0.435I 0.5294 0.1440 6.0HMJ 0.4275 0.6973 0.0851 6.0HM4 0.3074 0.7299 0.0074 6.0HM5 0.1949 0.5948 -0.0115 6.0HM6 0.2025 0.4270 0.0475 6.0CN1 0.4218 0.3378 0.1987 2.6(3)CN2 0.4288 0.4214 0.2406 3-8(4)CN3 0.4996 0.4255 0.2865 4.2(4)CN4 0.5633 0.3460 0.2905 4.5(4)CN5 0.5562 0.2623 0.2485 5.0(4)CN6 0.4855 0.2583 o.2oe6 4.2(4)HN2 0.3832 0.4783 0.2377 6.0HN3 0.5046 0 .4853' 0.3165 6.0HN4 0.6139 0.3489 0.3233 6.0HN5 0.6018 0.2054 0.2514 6.0hn6 0.4804 0.1984 0.1726 6.0CXI 0.0110 0.2004 0.1173 2.3(3)CX2 -0.0133 0.3038 0.1378 3-9(4)CX3 -0.0954 0.3200 0.1354 5*1(4)

CX4 - 0.1531 0.2327 0.1126 4 . 2 ( 4)

CX5 - 0.1289 0.1294 0.0922 * .5( 4)cx6 - 0.0468 0.1132 0.0945 3 -3 ( 4)HX2 0.0281 0.3662 0.1541 6.0HXJ -0.1128 0.3939 0.1500 6.0

hx4 -0.2119 0.2443 0.1109 6.0

HX5 - 0.1702 0.0670 0.0759 6.0HX6 -0.0294 0.0392 0.0799 6 .0CYl 0.1002 0.2366 0.0393 2 . 9 (4 )CY2 0.0432 0.3247 0.0163 3 .* (3 )CY3 0.0364 0.3684 -0.0371 *-3 (*)cy4 0.0865 0.32lf0 -0.0673 4 .0 ( 4 )CY5 0.1434 0.2360 - 0.0444 5-8 ( 5)cy6 0.1503 0.1923 0.0090 3 -6 (3 )HY2 0.0074 0.3564 0.0379 6.0HY3 - 0.0044 0.4314 -0.0535 6.0HY4 0.0816 0.3553 -0.1055 6.0HY3 0.1793 0.2043 -0.0660 6.0HY6 0.1911 0.1292 0.0255 6.0CZl 0.1367 0.0320 0.1138 2 -7 (3 )CZ2 0.1835 - 0.0200 0.1637 3 «1 (*)CZ3 0.20 J|0 -0.1387 0.1646 * .! (* )cz4 0.1778 -0.2053 O.U 57 4 . 7( 4)CZ5 0.1311 -0.1534 0.0658 5-3 (4)cz6 0.1105 -0.0347 0.0649 *-7 (4)HZ 2 0.2022 0.0277 0.1987 6.0

HZ3 0.2374 -0.1760 0.2003 6.0

HZ If 0.1925 -0.2902 0.1164 6.0HZ 5 0.1123 - 0.2011 0,0308 6.0

hz6 0.0771 0.0026 0.0292 6.0

TABLE XI-V

INTRAMOLECULAR BOND LENGTHS AND BOND ANGLES FOR CoH(CO)[P(CeH5)3]3

71

BOND LENGTHS BOND ANGLES

Co-H 1.41(9)8 H-Co-C 174(8)°Co-Pi 2.194(5)8 H-Co-Pl 86(8)°Co-P2 2.176(5)8 H-CO-P2 79(6)°C0-P3 2.195(108 H-C0-P3 79(5)°Co-C 1.704(17)8 Co-C^0 178(1)°C-0 1.194(20)8 Co-Pl-CAl 115.3(3)°Pl-CAl 1.871(9)8 Co-Pl-CBl 119.7(4)°Pl-CBl 1.847(9)8 Co-Pl-CCl 115.8(3)°Pl-CCl 1.870(9)8 CO-P2-CL1 117.2(3)°

P2-CL1 1.870(9)8 Co-P2-CMl 116.8(4)°P2-CM1 1.851(9)8 CO-P2-CN1 115.2(3)°

P2-CN1 1.860(8)8 Co-P3-CXl 119.7(4)°P3-CX1 1.876(9)8 C0-P3-CYI 112.0(4)°P3-CY1 1.872(9)8 C0-P3-CZI 117.1(3)°P3-CZ1 1.846(9)8

TABLE II-VI

c o h Cc o )[p (c 0h s)3]3

STRUCTURE FACTOR TABLE (CALCULATED AND OBSERVED STRUCTURE FACTORS

ARE TEN TIMES ACTUAL VALUES)

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■cv it- a M l itf /-Ml Hi «l* • •ftft ■1* •-IK in at- • •it n * t.• Tti 1141 ri* a M f M B t-Ml ♦ti ai- a *«• <1* r-•to </• at- • tar IB/ill ■it t- ♦ m Ml i-lit nr ♦• a ■a* *11 i -Ml • 14 H • 1- i ft# tri 44-Ml 11/ t* B car ru • r-• *•1 •Ml ft- • u r •if 1 1-*4*1 trti t- • «•/ •re •1 +4*4 *M ft. Bi­ •it in tt-••a Hi ll- t- «*t r n *1-fft# an •- •- o h •it ik-tir Ml t- •* NKI MCI li -*•4 *M #• •- *- CiV ■I# ii-tie *n 1- *- f- ♦IV Itt M-4/4 ctr *1- •- ftft* ♦•a ai-JTC ttt • 1- •- 1*1 •14act •rr ft- •- ••■ icr •-♦ft# •<* 1- *- ■If •#» V-441 1 A# 1* ■- ill **f 4-Ilf </• •- ■- t«r »•• 4-IK fit r- ■. M M ■ Ml *-Hi Ht I- ft­ 4CI K* • -4*1 li# ftl* <- tte ft* ft.44ft CM II- c- ••a 41* a-ur •rr ri- <* *- *ac ecr t-nt • IB #1* c- tir ■14 4-•ir ■ fr# II' 4- f W M B 4-<tf nr ■ • 4- Ita •It 1 •tit ut 1* 1- ■if Iff ♦a*•I* ftftC 1- i~ ♦* - •ftl ■re ft.IM IB* +- 4- r*4 lii * i-Jft# MC t* c- ■ii •If *i-1t* CM *- c- ##• •at 4 t“tt* ViB 1- i- *- ■it •tt 41-41* lit I* 4- «ni • Ml 11-• 1* tft ih u Htt MICIlf HC 11- t- ♦ art 4141 *-c<r CM tl- •- ttt *1* •*#*■ ♦a* cl* t. *- icti H 1 1 ft­Ct/ ut «i- ft* iti lift ft-•n Hi II- *- ft­ 4 B*P ||HMi ■ Ci *i- ft­ **v •re V- ft.•*r ICC ft. •- ftir in ft-4*1 Ul ft. *- ft. an in 4+• ** via <• i- cat u t • 1*<r« •cr c* ft- •VI HI •-4»» ■ tc <- ♦- ■ BZ •VI ft­itr •it ft- i- tftt flf ft.l*f ■cr *• ■- ■ i* ttf 1-Mft ■it c* V- 1V1 111 CT- t-iftt Tit r- *- /•■ Cft* 11- •-il* 14* a- h ft- ■ft art 11- •-fti# •Cl i- •- ■1/ HI • 1- a-MC Ivr i- ft­ M i III ft. •-•Cl IM tt- *. H C ♦I* ft. ft-ftft# *■# ■i- w *■• M* ■ - •-1*4 m b 41- •- IM • *C *- •-etc •/# • 1- ft­ Iff (■» 1-• 1* *<■ tl- ft­ ire i*r 1- •-lar ■ at tt- *- ft> ♦re fa# 11- 4-•if /<■ ■ 1- B- <•1 1*4 • 1* *-ur CM ll~ ft- *- 1B4 H I ti­ 4-*<t If* ai- t- Cl# fir ll- i-■ ti <M •t- •• H I rv a li­ 4-ftli • It it- ■» #1* 444 fti­ 1 -*44 err n-1- ft- IU 41* n' t-•1 • /•r • i- a- •- ■41 4*4 ft­ 4-Bit it* B1 • t- ti* Vi* ft. 4-til H I •* ■- ft­ U * 4** ■* <-we K4 ft- V- H C nr 4- <-Mt Clt i* 1- ri* it* i- /* h-rtf ire *- t' ft* itf H I B- <•II* fit t- 1- ■ at •ta *. J-ft*/ Ul V- ft- M f Ci# a- j. 1.*1« 144 1- 4- itr 144 •- 4-nt ati I- *' ar* •<t ■ - <-#*■ • I* It- *- *4* ftl* e- /• ft­etc <■• ■ I- *• 1/4 *•« r- 4-t*r tee J I* *- ••■ ■ 11 4T- ft­ii* ti* IT- *♦ f- iff «*v 11- ft. ft.« * • 1« tl- *- cat <ftt • 1- ft­tit 144 ■ 1- ** t- v/a 41- ft.r«i H/ <■- *- ■Bv * K 41-fti tea Cl* a- M l ■ ■< Bi­ 1-••a H I 11* t- ■ #• • ta ll*•VC in 11* *- 41* lii •1- ft.•** ■/• • I- *- #*V KC ft-lea •ft* ai - *- «■< ■at • - •*•4/ lit 1- a* cac ♦•a ft- ft­•ii ■tv 4- •- H I ■tr •- ft*•ri *14 ftft *- <4# M i I- ft* V•if •ti f- ft- tie 444 4- ft­•IB MB c* ** I M Ilf 14- ft.IM *CC f- *- at* III • t- t-*♦* iia 1- i- H C •a# 41-If* CIV I- ft* tti car |l» a-•tl rti I h «ft Kt tit ■ 1“ a.etc ru • 1- 4* •f* •ai rt- a- p.ell 14/ cl- 1- ill MC <t- i- ft.♦ f# err •1- I- ♦*r 1 IB • i* a.tftt cat • 1* c- ♦1# H I ii- ■-ftft# cat < I* c- • IV H « M- i-ftftft ri- c- lit H t ft* a-twl in 41* # * la* M t •- •-!■• ■ IB ii- i- I N ere •* B- ft-Ill lea *i- r- ee* ait <- 1-HI 111 •- <* m ♦tt *- 1-ail lea a* /* •a# 4*4 i- ■-•if III 1- c- alt 14 a *- ft-HI IH 4- C- ■if m i- ■*

DISCUSSIOM

Figure 2-2 presents a stereoscopic view of CoH(CO)-

[P(C6H5)3]3. Figure 2-3 illustrates the stereoscopic pair based on the cobalt coordination sphere (the nine phenyl rings are deleted) with 50$ probability ellipsoids indicating the modes of anisotropic thermal motion for the non-hydrogen atoms and a 50$ probability sphere

for the isotropically vibrating hydride atom. The cobalt atom lies0.31& from the equatorial plane defined by the three phosphorous atoms

( -6.67x + I0.23y - 2.10z = O.93). The Co-C-0 angle of 178(1)° and the H-Co-C angle of 17^(8)° do not differ significantly from a linear angle of 180°. The H-Co-P angles of 86(8)° for PI, 79(6)° for P2, and 79(5)° for P3 are statistically equivalent.

There is no significant difference In the three values listed in Table II— V for the Co-P bond distances. The mean value of 2.188(8)5 compares favorably with the mean value of 2.192(6)5 reported by Davis, et _al.,ae for the six Co-P bond lengths arising from the two crystallo- graphically independent molecules CoH(N£)[P(CqHs)3]3 . Titus, et al. , 29

report * mean of 2.113(3)5 for the four Co-P bonds in CoH[f(c0Hs)- (0C2Hs)2]4j and Frenz and Ibers30 cite a mean of 2.052(5)5 for the four Co-P values in CoH(PF3)4. This decrease in Co-P bond length parallels the increase in TT-acceptor character of the phosphlne ligands.

In Figure 2-if the windmill-llke nature of the triphenyl- phosphine ligand is illustrated. The view is perpendicular to the xy plane with Pi and the attached phenyl carbons (rings A, B, C) the only atoms illustrated, (This view is approximately equivalent to looking down the Pl-Co bond vector.) The P-C bond distances listed

75

76in Table II-V are statistically equivalent (mean «* 1.863(3)18). These values are shorter (as would be expected) than the values of 1.822(5)5 ,

1.831(5)5, and 1.831(5)5 (mean » 1.828(3)5) reported by Daly 31 for the free trlphenylphosphine molecule.

For the Co-C-0 moiety the Co-C bond distance is 1.704(17)5

and the C-0 bond length is 1.194(20)5 . These compare remarkably well with the electron diffraction values reported in 1939 4y Ewens and Lister1 for CoH(C0)4 (Co-C mean 1.815 and C-0 mean 1.1 6.5). even though the hydride position was misinterpreted. For Co(SiCl3)(CO)4,32 Robinson and Ibers have reported Co-C values of 1.751(9)5 , 1.775(9)5 , 1*773(9 )5 , and 1.797(9)5 and corresponding C-0 values of 1.167(8)5 ,1.11|0(9)S, 1.146(8)5 , and 1.136(8)5 which are not significantly dif­ferent from the values reported in this work. The values of 1.784(13)5

and 1.829(12)5 for Co-N and 1.101(12)5 and 1.123(13)5 for N-N reported for the isoelectronic CoH(N2) Qp(CeH5)3]3 are also comparable.

Table II-VII lists the Intramolecular and intermolecular contact distances less than or equal to 2.605 (excluding the intra- (individual)-ring distances). Using the covalent radii listed by Pauling33 for hydrogen (1.28) and phosphorous (I.9S) as basis for comparison, the sum of the three intramolecular H-P contact distances should be greater than 3 .18. However, values of H-Pl = 2.53(18)8,

H-P2 “ 2.36(14)8, and H-P3 » 2.38(12)8 are obtained for CoH(CO)- Cp(c6Hs)3 ]3. In addition there are three hydride to ortho-hydrogen Intramolecular distances within the 2.b5 value obtained for the sum of two covalent hydrogen radii. These values are H-HB6 = 2.22(14)8, H-HL2 ® 2.09(15)8, and H-HZ2 = 2.12(12)8. The hydride atom is effec­

tively shielded by the three phosphine ligands and three of the phenyl

77ring ortho-hydrogens. A similar situation is noted In the report on IrH(CO)2[P(CQHs)3]2,34 with the hydride held In position by two carbons of the equatorial carbonyl groups and an ortho-hydrogen of the equa­torial trlphenylphosphine ligand at a distance of ca. 2.3$.

To date, thirteen five-coordinate transition metal hydrides have been examined by X-ray crystallographic methods (Table II-VIIl). The hydride atom has been approximately located in only seven of these compounds. With the exception of the pseudo-tetrahedral compounds RhHCP(C6H5)3]4,;L0 RhH[j*(C6H5)3]3[As(C6H5)33,38 and CoH(PF3)4,3° the coordination geometry of all crystallographlcally examined transition metal hydrides is trigonal bipyramidal. It is Interesting and puzzling to note that the hydride atom was not located in the three pseudo- tetrahedral structures.

For the compounds in which the hydride atom was detected, It can be noted that the three equatorial ligands are displaced towards the hydride ligand. Maximum distortion of O.A98 occurs for four phos- phine ligands in CoHCp(CqHs)(OC2Hs)2]4.29 Minimum displacement of

0.238 occurs for two phosphine ligands in IrH(CO)2[p(C6H5)3]2.34 The average displacement for three phosphine ligands is O.328. Replace­ment of the very bulky phosphine ligands (the approximate volume

occupied by a trlphenylphosphine is 37583) in an axial position with much less bulky ligands such as Na or CO (the volume of CO is approxi­mately 438s) will remove most of the sterlc strain and allow the con­figuration to approach the ideal trigonal bipyramidal form.

Frenz and Ibers, who reported the highly distorted tetra­hedral CoH(PF3)4 (P-Co-P angles of 101.8(3)°, 108.2(2}°, 109.7(2)°, and 118.0(2)°) propose four alternative models for placement of the

hydride ion, each model resulting in a distorted trigonal bipyramid.One model positions the H on the tetrahedral edge with the greatest P-Co-P angle (118.0(2)°), thus placing the h” in an equatorial posi­tion. (The axial PF3 groups would be displaced towards the H~ and the equatorial PF3 would be displaced away from the H .) Alternatively, the H ion may be located in a tetrahedral face, thus Implying a dis­ordered crystal structure because of the crystallographlc C2 axis passing through the molecule. Two possible models with two-fold dis­order arise with a statistical average of fa H in two tetrahedral faces. A fourth model with four-fold disorder is also proposed with a statistical average of ^ H in each of the four tetrahedral faces.For these three disordered structures the electron density of the H~, which would be in an axial position, would be distributed over a large area and would be difficult.to detect. (Frenz and Ibers favor the two-fold disordered models.)

Ilmaier and Nyholm prepared both the RhH[P(CQHs)3]4 41>4S and RhH[P(C^H5)3]3[A8(C6H5)3]38 molecules. There was considerable confu­sion in the literature concerning the preparation of the first compound. The authors were unable to duplicate the nmr spectrum (in particular, no Rh-H signal was observed) as reported by Dewhlrst, ct al.43 (Dewhirst, et al., suggested a trigonal bipyramidal model for the RhH[P(CeH5)3]4 molecule, based on interpretation of some rather unusual nmr data.) The only evidence offered for the latter compound were ir bands at 2125 and 2180 cm"1 attributed to two Rh-H stretching bands arising from location of the H” trans to both P and As atoms. Baker and Pauling were unable to locate the H in either compound (the latter compound also had a disorder problem with the As and P atoms randomly occupying

79the four tetrahedral locations.) It Is indeed possible and probable that there was no hydride ion present to be detected nor to exert any stereochemical influence.

For the remaining three compounds in which the hydride ion was not observed the geometry is trigonal bipyramidal. tn hydrldo-

carbonyl(fumaronitrile)bis(trlphenylphosphine)iridium(l), IrH(CO)- [p(C6H5)3](C4H ^ 2) the hydride was unobserved due to the crystal- lographically imposed disorder requiring 50$ occupancy of the apical sites by both CO and H. IrH(N0)[P(C6H5)3]3[Cl04]39 crystallized in a noncentrosymmetric space group, thus decreasing the chances for ob­servation of the hydride ion.

Thus it can be concluded that the hydride ion does Indeed exert stereochemical influence. The preferred geometry for truly five-coordinate transition metal hydrides is trigonal bipyramidal. Distortions arise from attempts to minimize the electronic repulsions between the non-hydride ligands, with maximum displacement towards the hydride ligand. Additional X-ray and neutron diffraction data for five-coordinate hydrides should support this hypothesis.

FIGURE 2-3

ORTEP STEREOSCOPIC DRAWING OF THE COBALT COORDINATION SPHERE

(WITH 3056 PROBABILITY ELLIPSOIDS)

FIGURE 2-1*

ORTEP STEREOSCOPIC DRAWING OF THE TRIPHENYLPHOSPHINE LIGAND (VIEWED APPROXIMATELY DOWN THE Pi-Co BOND VECTOR WITH 5O# PROBABILITY ELLIPSOIDS. HYDROGENS ARE OMITTED FOR CLARITY.)

TABLE II-VII

INTRAMOLECULAR AND INTERMOLECULAR CONTACT DISTANCES £ 2.608 FOR CoH(CO)[P(CeH5)3]3

(EXCLUDING INTRA-(INDIVIDUAL)-RING INTERACTION)

Intramolecular Contact Distances (£)

Intermolecular Contact Distances (A)

H-Pl 2.53(18)H-P2 2.36(14)

H-P3 2.38(12)

h-hb6 2.22(14)H-HL2 2.09(15)H-HZ2 2.12(12)

C-HX2 2.511(18)0-HC2 2.582(13)

CL1-HN6 2.501(10)

CM1-HL6 2.523(15)

HA2-HZ2 2.422(13)HA.6-HC2 2.485(13)

HX6-HZ6 2.544(13)HY6-HZ6 2.448(13)

o-hz4 2.512(15)

HA2-HZ2 2.422(13)HZ3-Hz6 2.510(11)

HB2-HY5 2.431(14)HB5-HM2 2.293(12)

HL3-NH4 2.494(11)HN3-HN6 2.452(13)

HY2-HY3 2.456(13)HZ6-HZ6 2.448(13)

TABLE II-VIII

FIVE-COORDINATE TRANSITION METAL HYDRIDES

Formula

CoH(C0)[p(GeH5)3 ]3CoH(Ns)[p(CeH5)3]3

CoH[P(C^H5)(OCsH5)a]4

RuHC1[p(C0H5)333

RhH(CO)[P(CeH5)3]3RhHCl(S1C13)[P(CeH5)3]g•xS £HC13

IrHCcoJsCpfCeHsJaJsCoH(PF3)4RuH(NO)[P(CsHs)3]3RhHCP(C6H5)3]4*iC6HB

RhH[P(C6H5)3]3[A8(CeH5)3]-iC6HaIrH(NO)[P{C6H5)333[C104]IrH(CO)CP(C6H5)3](G4H2N2)

M-H

Metal to Equatorial Ligand Plane Distance Ref.

1.40(10)8 0.3181.64(11)81.67(12)8

0.3280.288 28

1.38fia 0.498 29

1.70(15)5 b 351.60(12)8 O.368 10

1.468 c 361.66(20)8 0.238 34

— 0 .598d 30— 0.358 37— 0.70ge . 12

— c 38— O.5I8 39_ _ c 40

a. "Refined" 1.548.b . Hydride equatorial.c. Disorderd. For proposed trigonal bipyramidal model with H on 3-fold axis.e. Assume H occupies position on 3-fold axis trans to one ligand.

REFERENCES1. R. V. G. Ewens and M. W. Lister, Trans. Faraday Soc.» 55( 1959)681.2. W. Hleber and F. Leutert, Naturwlss., 19f1951)360.3- W. Hleber and H. Schulten, Z. Anorg. Chem., 232(1937)29.I*. W. Hleber, Die Chemle. H ( 19l*2) 2l*.5. W. Hleber, F. Seel, and H. Schneider, Chem. Ber., 85f1952)61*7.6 . B. A. Frenz and J. A. Ibers, In E. L. Muetterties (Ed.), The

Hydrogen Series. Vol. I, Marcel Dekker, Inc., New York, 1971*

P. 33“7^.7. M. L. H. Green and D. J. Jones, In H. J. Emeleus and A. G. Sharpe

(Ed.), Advances In Inorganic Chemistry and RadlochemlBtry. Vol. VII, Academic Press, New York, 1965* P- Il5“l83-

8. J. P. Jesson In E. L. Muetterties (Ed.), The Hydrogen Series. Vol. I, Marcel Dekker, Inc., New York, 1971* P* 75_202.

9. P. G. Owston, J. M. Partridge, and J. M. Rowe, Acta Crystallogr.. 12.(1960) 21*6 .

10. S. J. LaPlaca and J. A. Ibers, J. Amer. Chem. Soc.. 85(1965)5501: Acta Crystallogr.. 18(1965)511.

11. S. C. Abrahams, A. P. Ginsberg, and K. Knox, Inorg. Chem..

1(1961*) 558.12. R. W, Baker and P. Pauling, Chem. Comm.. (1969)11*95-13. A. Misono, Y. Uchida, M. Hidai, and T. Kuse, Chem. Comm.. (1968)981.ll*. S. Otsuka and M. Rossi, J, Chem. Soc. (A), (1969)1*97-15. G. B. Tupper, Ph.D. Dissertation, Louisiana State University at

Baton Rouge (1971*) -16. S. F. Watkins, "ORIENT, A Fortran IV Computer Program for Orienta­

tion on the Enraf Nonius PAD-3 Diffractometer," Louisiana State

88

University at Baton Rouge (I969).17. J. M. Stewart, "XRAY '67, A Fortran Computer Program System for

X-Ray Crystallography," University of Maryland (I967).18. S, F. Watkins, "DIFSET, A Fortran IV Computer Program for Gener­

ating Settings and Control Cards for the Enraf Nonius PAD-3 Dif­fractometer," Louisiana State University at Baton Rouge (1970).

19. S. F. Watkins, "DXFDAT, A Fortran 17 Computer Program for Reducing Data Collected on the Enraf Nonius PAD-3 Diffractometer,"Louisiana State University at Baton Rouge (I97O).

20. International Tables for X-Ray Crystallography. Vol. I, Interna­tional Union of Crystallography, Birmingham, England, 2nd ed., 1965.

21. H. P. Hanson, F. Herman, J. D. Lea, and S. Skillman, Acta Crystallogr.. lft 1961*-) 101*0.

22. M. C. Williams, "ECALC, A Fortran IV Computer Program for Calculat­ing Normalized Structure Factors," Louisiana State University at Baton Rouge (1972).

23. P. Main, M. M. Woolfs on, and G. Germain, "MULTAN, A Computer Program for the Automatic Solution of Crystal Structures," University of York, England, and University of Louvain, Belgium (1971)•

2l*. I. L. Karle in F. R. Ahmed (Ed.) , Crvstalloaraphic Computing.Munksgaard International Booksellers and Publishers Ltd.,

Copenhagen, Denmark, 1970* P* 19"25-23. S. F. Watkins, "KBANG, A Computer Program for the Calculation of

Rigid-Body Angles," Ph.D. Dissertation (Appendix i) , University of

Wisconsin (19&7)•26. W. R. Busing, K. 0. Martin, and H. A. Levy, "0RFLS, A Fortran

Crystallographic Least-Squares Program," ORNL-TM-305* Ridge

National Laboratory (1962); "ORFLSD, A Fortran Crystallographic Least-Squares Program Adaptation o£ ORFLS for Rlgid-Body Refine­ment," University of Wisconsin (1969)*

27. C. K. Johnson, "ORTEP, A Fortran Thermal-Ellipsoid Plot Program for Crystal Structure Illustrations," ORNL-3794, Oak Ridge National Laboratory (1965)•

28. B. R. Davis, N. C. Payne, and J. A. Ibers, Inorg. Chem., 8(1969)2719 and J. Amer. Chem. Soc.. 91(1969)1240.

29. D. D. Titus, A. A. Orio, R. E. Marsh, and H. B. Gray, Chem. Comm.. (1971)322.

JO. B. A. Frenz and J. A. Ibers, Inorg. Chem.. £(1970)2403.31. J. J. Daly, J. Chem. Soc.. (1964)3799.32. W. T. Robinson and J. A. Ibers, Inorg. Chem., 6(1967)1208.33* Pauling, The Nature of the Chemical Bond. Cornell University

Press, Ithaca, New York, 3rd ed., i960, p.. 260.34. M. Ciechanowicz, A. C. Skapski, and P. G. H. Troughton, Collected

Abstracts, VHIth International Congress of Crystallography, Stony Brook, N. Y., 1969> P- sl72; Acta Crystallogr.. 12(1969)s!72.

35. A. C. Skapski and P. G. H. Troughton, Chem. Comm.. (I968)1230.36. K. W. Muir and J. A. Ibers, Inorg. Chem.. £(1970)440.37- C. G. Pierpont and R. Eisenberg, Inorg. Chem.. 11( 1972) 109*1.38. R. W. Baker, B. Ilmaier, P. J. Pauling, and R. S. Nyholm, Chem.

Comm., (1970)1077.

39. D. M. P. Mingos and J. A. Ibers, Inorg. Chem., 10(1971)1^79.40. K. W. Muir and J. A. Ibers, J. Organometal. Chem.. 18( 1969) 175.1*1. B. Ilmaier and R. S. Nyholm, Naturwiss., 56(1969)415.

B. Ilmaier and R. S. Nyholm, Naturwiss.. 56( 1969)656.K. C. Dewhlrst, W. Keim, and C. A. Reilly, Inorg. Chem.

2(1968)51*6 .

APPENDIX

DI-n-(DIMETHYLGERMANYLENE)-BIS[TRICARBONYL-(trimethylgermanyl)rutheniumCIII)]

92

The preliminary crystal data for di-p-(dimethylgermanylene)- bis[tricarbonyl(triraethylgermanyl)ruthenium(lIl)] had been collected and analyzed when another member of the research group, Madeleine Crozat Williams, solved the structure of the silicon analogue, di-p- (dimethylsilylene)-bis[tricarbonyl(trimethylsiiyl)ruthenium(III)]j1

due to an Incorrect molecular formula inscribed on the sample vial label. The structure of the tin analogue, d1-p-(ditnethy 1 stannylene)- bis[tricarbonyl(trimethylstannyl)ruthenium(lIl)], had been solved earlier by Watkins.s As the three compounds are all isostructuial It was decided to abandon the search for a crystal suitable for data col­lection on the diffractometer. The crystal data that were determined are listed in Table A-I.

The yellow, truncated triangular plate-like crystals of [(CH3)3Ge(CO)3RuGe(CH3)£]s were produced in the multi-product reaction of trlruthenium dodecarbonyl and trimethylgermane.3 The crystals are monoclinic, space group P2x/c. Cell dimensions were determined by

film methods, using both molybdenum and copper radiation with wave­lengths of O.7IO7& and 1.5J+18&, respectively. Cell constants are a - 10.80(1)8, b = 9.542(3)8 , c « 14.07(2)8, and 0 « 108.6° with

= 2.00 g/cm3 and Z = 2. There were not sufficient crystals available for determination of the experimental density.

9?

TABLE A-I

CRYSTAL DATA COMPARISON FOR THREE RtigA^C^gHgoOg MOLECULES

95

A - SI Ge SnMolecularWeight 632.9 810.9 995.CrystalSystem Monoclinic Monoclinic MonoclinicSpaceGroup P2jl/c P21/c P2i/c

a = 10.64(1)8 lo.8o(l)& 11.22(2)8b “ 9 -5W ( 5)& 9.3te(3)8 9.22(2)8c = 14.00(2)8 14.07(2)8 14.39(2)8

0 * 109.4(2)° 108.6° 105.3(1)°' V = 1391 a® 1348 a3 1436 a3

D 01 c 1.23 g/cm3 2.00 g/cm3 2.22 g/cm3D = e — — 2.2 g/cm3Z = 2 2 2

REFERENCES

1. M. M..Crozat and S. F. Watkins, J. Chem, Soc.(Dalton),, (1972)2512.2. S. F. Watkins, J. Chem. Soc. (a ), (1969)1552.5* J* Howard, S. A. R. Knox, F. G. A. Stone, and P. Woodward, Chem.

Comm,. (1970)1^77.

96

VITA

Johnnie Marie Whitfield was born on May 25, 19^5 , the first of four children of Lucy Sellers and Benjamin Hatch Whitfield. She received a diploma from William B. Hurrah High School in I96I and a B.S. cum laude with Honors in Chemistry from Millsaps College in 1965. Both schools are located in her native Jackson, Mississippi.

Graduate studies were begun in I965 at Vanderbilt University in Organic Chemistry and in the Summer of 1966 at George Peabody Col­lege in Music. Then she served as an Instructor of Chemistry at Alabama College in Montevallo, Alabama (now The University of Monte- vallo) for twelve months prior to enrolling in the Graduate School of Louisiana State University at Baton Rouge. During the Summer of 1972

she served as an Instructor of Chemistry at Millsaps College. At the present time she is a candidate for the Degree of Doctor of Philosophy in Inorganic Chemistry at Louisiana State University at Baton Rouge.

97

EXAMINATION AND THESIS REPORT

Candidate: Johnnie Marie Whitfield

Major Field: Chemis try

Title of Thesis: The Crystal and Molecular Structures of Trans-diiodot.etrakis (para-tolylisocyano)iron(ll) and J&sas-hydridocarbonyltris- (triphenylphosphine)cobalt(jj.): Chemical Bonding Implications

Major Professor and Chairman

Dean of the Graduate School

E X A M I N I N G C O M M I T T E E :

D a t e of Examination:

November 28. lQT^