Binuclear phosphido-bridged tungsten-rhodium complexes. Crystal and molecular structure of the dimeric bimetallic complex [(CO)4W(.mu.PPh2)2Rh(.mu.CO)]2 with a bent metal chain

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Binuclear phosphido-bridged tungsten-rhodium complexes. Crystal and molecular structure of the dimeric bimetallic complex [(CO)4W(.mu.PPh2)2Rh(.mu.CO)]2 with a bent metal chain
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  Organometallics 1987,6, 101-109 101 Binuclear Phosphido-Bridged Tungsten-Rhodium Complexes. Crystal and Molecular Structure of the Dimeric Bimetallic Complex zyxwv   CO),W(p-PPh2)2Rh(p-CO)]2 with a Bent Metal Chain Peter M. Shulman, Eric D. Burkhardt, Eric G. Lundquist, Robert S. Pilato, and Gregory L. Geoffroy’ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJ Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 Arnold L. Rheingold Department of Chemistry, University of Delaware, Newark, Delaware 1971 Received February 7, 1986 The new phosphido-bridged W-Rh complexes zyxw CO),W p-PPh2),RhH CO) PPh3) 2)) (CO),Wr(,- PPh2)2RhH(COD) 3; COD = 1,5-~yclooctadiene), nd CO)4W p-PPhz)2Rh cyclooctenyl) 4) have been prepared and characterized. Complex 2 has been structurally characterized: zyxw 2Jn, a = 11.430 (3) A, b = 19.085 5) A, c = 20.738 (6) A, p = 100.80 (2)O, V = 4444 (2) A3, zyxw   = 4, R = 0.0393, R, = 0.0420 for 5754 reflections with F, > 4a(F0). The two w-PPh, ligands bridge the W-Rh bond with the W further coordinated by four COS and the Rh by hydride, CO, and PPh3 ligands. Complex 4 reacts with CO to yield the tetrametallic complex [ CO),W p-PPh,),Rh p-CO) 13) which has been structurally characterized: P1 a = 13.580 (2) A, b = 19.838 (4) A, c = 22.299 5) 1, y = 82.94 2)O, /3 = 79.17 (2)O, y = 88.63 2)O, V = 5857 2) A3, zyxwvutsrq   = 4, R = 0.0619, R, = 0.0699 for 6749 reflections with F, > 3a(F0). Two crystallographically independent but chemically similar molecules form the asymmetric unit; the two molecules form an enantiomeric pair. The four metal atoms of each molecule are arranged in a bent chain with the W atoms at the end and the Rh atoms in the middle of the chain, and all metal-metal distances are consistent with single metal-metal bonds. The two Rh’s are bridged by two carbonyl ligands, and the W-Rh units are each bridged by two r-PPh, ligands. Complex 13 rapidly reacts with CO/H2/PPh3 o cleave the Rh-Rh bond and form complex 2. This latter complex was found to readily react with ethylene to transform one of the p-PPh, bridges into a PPhzEt ligand and give CO)4 PPh2Et)W p-PPh2)Rh CO) PPh3). imilar bridge elimination occurs when the anionic complex [ CO)4W p-PPh2)2Rh CO) PPh3)]- s treated with , CH30Tf. Heterobimetallic complexes offer the promise of unique reactivity as a result of combining metals with inherently different sets of chemical properties.’ One problem that must be solved in order to fully exploit this potential lies in the relative ease with which many .of these fragment when placed under reaction conditions. In our studies we have used the p-PPh, ligand to bridge adjacent metals so as to retard such fragmentation reactions, and these ligands often serve that purpose well. However, p-PR, ligands are not inert as they can participate in reaction chemistry, often in unwanted ways., The p-PPh, ligand was selected in large part because of the utility of these ligands in directing the syntheses of desired compounds via the “bridge-assisted” synthetic pathway.l An illustration is the preparation of the p-PPh2 1) Roberts, D. A.; Geoffroy, G. L. In Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.; Pergamon: Oxford, 1982; Chapter 40. 2) a) Geoffroy, G. L.; Rosenberg, S.; Shulman, P. M.; Whittle, R. R. J. zyxwvutsrqponml m. Chem. SOC. 984, 106 519. b) Harley, A. D.; Guskey, G. J.; Geoffroy, G. L. Organometallics 1983, 2, 53. c) Burkhardt, E. W.; Mercer, W. C.; Geoffroy, G. L.; Rheingold, A. L.; Fultz, W. C. J. Chem. Soc., Chem. Commun. 1983, 1251. d) Rosenberg, S.; Whittle, R. R.; Geoffroy, G. L. J. Am. Chem. Sac. 1984, 106, 5934. e) Klingert, B.; Werner, H. J. Organomet. Chem. 1983,252, C47. 0 Werner, H.; Zolk, R. Organometallics 1985, 4, 601. 9) Maclaughlin, S. A.; Carty, A. J.; Taylor, N. J. Can. J. Chem. 1982,60,87. h) Patel, V. D.; Taylor, N. J.; Carty, A. J. J. Chem. SOC., hem. Commun. 1984,99. i) Smith, W. F.; Taylor, N. J.; Carty, A. J. J. Chem. SOC., hem. Commun. 1976,896. (i) Regragui, R.; Dixneuf, P. H.; Taylor, N. J.; Carty, A. J. Organometallics 1984,3,814. k) Seyferth, D.; Wood, T. G.; Fackler, J. P., Jr.; Mazany, A. M. Organometallics 1984,3, 1121. 1) Henrick, K.; Iggo, J. A.; Mays, M. J.; Raithby, P. R. J. Chem. SOC., hem. Commun. 1984,209. m) Yu, Y.-F.; Chau, C.-N.; Wojcicki, A.; Calligaris, M.; Nardin, G.; Balducci, G. J. Am Chem. SOC. 984, 106 3704. n) Shyu, S.-G.; Wojcicki, A. Or- ganometallics 1984,3,809. 0) u, Y.-F.; Gallucci, J.; Wojcicki, A. J. Am. Chem. SOC. 983, 105 826. 0276-7333/87/2306-0lO1$01.50/0 bridged W-Ir complex 1 by the reaction sequence given in eq l., Compound 1 gave rise to an interesting series W(CO&(PPh2H)2 BULI ICW(CO)~(PP~~H)(PP~~)I BuH +tr.ns-IrCI(CO)(PPh3)? (1) y2 (CO),WeIrHCO)(PPh3) t LlCl PPh3 ‘PPh2 1 of binuclear acyl-hydride and carbene-hydride derivatives, but it showed no examples of unusual bimetallic reactivity., This we believe is in part due to the inertness of the Ir(3+) center in this complex. We have sought to increase the reactivity of the above class of compounds by two strategies. In work to be re- ported el~ewhere,~ he CO and PPh, ligands on the Ir center have been replaced by a 1,Bcyclooctadiene (COD) ligand. The latter has the potential to yield open coor- dination sites on Ir by hydrogen transfer to the olefin ligand. In the present study, we have chosen to replace Ir by the more reactive metal Rh, as well as incorporate a COD ligand. Herein is described the preparation of new bimetallic W-Rh complexes 2, 3, and 4. Complex 2 is particularly interesting since the coordi- nation environment of the Rh end of the molecule resem- bles RhH(CO)(PPh,),, a well-known hydroformylation 3) Breen, M. J.; Shulman, P. M.; Geoffroy, G. L.; Rheingold, A. L.; 4j Rosenberg, S.; Mahoney, W. S.; Hayes, J. M.; Geoffroy, G. L.; Fultz, W. C. Organometallics 1984, 3, 782. Rheingold, A. L. Organometallics 1986, 5, 1065. 1987 American Chemical Society  102 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA rganometallics, Vol. 6, No. 1, 1987 Shulman et al. zyxwvutsrq 2 zyxwvutsrqp   4 cataly~t.~ hus, if such a complex were to show catalytic activity, it would be interesting to explore the effect of the adjacent metal W on its catalytic properties. However, as described herein and previously communicated,28 complex zyxwv   is not a suitable catalyst since it readily undergoes a bridge-elimination reaction in the presence of olefins. From complex 4, a new tetrametallic W2Rh2 omplex with a bent metal chain has been prepared and structurally characterized, and those results are also described herein. Results and Discussion Syntheses. The new complexes were prepared by using the bridge-assisted methodl beginning with the phosphi- dometalates zyxwvuts   and 6 prepared in situ by the reactions of eq 2. From these, the anionic complexes 7 and 8 were CBULI (1 eauiv) LI zyxwvutsrqponmlkjihgf (COL(P P h 2 H ( PP h 2) 5 ( 2) L12CW(C0)4(PPh2)21 t BuLi (2 equiv) 6 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDC (C 0)4( P Ph2H 2 obtained by reactions 3 and 4. These anionic complexes p2 /\ 6 t trans-RhCI(CO)(PPh3)2 LI C(C0)4W,-Rh(CO)(PPh3)1 3) PPhZ 7 p2 ‘ CI /\ 6 + ’/,(COD)Rh RhfCOD) LIC~CO)~W’--\R~(COD)] (4) Phz \CI’ 8 have proven too unstable to isolate in pure form, but their conversions to the well-characterized complexes described below and the spectroscopic data for 7 eave little doubt as to their formulations. Spectroscopic data for all the new complexes prepared in this study are given in the Exper- imental Section with 31P NMR data listed in Table I. At -61 “C, the 31P NMR spectrum of 7 hows a doublet at 6 202.9 (Jp-Rh = 139.2 Hz) due to equivalent p-PPh, ligands and a second doublet at 6 45.3 (Jp-Rh = 189.9 Hz) assigned to the Rh-PPh, ligand. The downfield position of the p-PPh, resonance implies the presence of a W-Rh bond in 7,6 nd the absence of 31P-31P coupling indicates a tetrahedral ligand arrangement about Rh.’ Upon warming to room temperature, the 31P NMR spectrum broadens, but the resonances still show lo3Rh-,lP coupling and do not shift in position. While the reasons for this broadening (5) Jardine, F. H. Polyhedron 1982, I, 569. (6) (a) Petersen, J. L.; Stewart, R. P., Jr. Inorg. Chem. 1980,19, 186. b) Carty, A. J.; Maclaughlin, S. A.; Taylor, N. J. zyxwvut . Organomet. Chem. 1981, 204, C27. (c) Garrou, P. E. Chem. Rev. 1981, 81, 229. (d) Jo- hannsen, G.; Stelzer, 0. Chem. Ber. 1977,110,3438. (e) Carty, A. J. Ado. Chem. Ser. 1982, No. 196, 163. (7) (a) Mazanec, T. J.; Tau, K. D.; Meek, D. W. Inorg. Chem. 1980,19, 85. (b) Kanz. S. K.: Albrieht, T. A.; Wright, T. C.; Jones, R. A. Or- Table I. NMR Data in C6D, Solution J(P-P), J(P-Rh), J(P-W), complex F(p-PPh,) 6(PR3) Hz Hz Hz 2 166.4 dd ... 33.0 107.5 161 3 19013 d 4 211.0 d 7 202.9 d 9 89:3 ddd 10 93:l ddd ... ... ... 13 206.0 d a Unresolved. 53.9 dt 33.0 163.6 ... ... .,. 104.0 170 ... .I. 135.9 180 ... .,. 139.2 151 45.3 d ... 189.9 ... ... 177.9, 21.7 89.0 a 30.2 dd 178.6 139.9 ... 8.29 d 22.4 ... a ... 181.3, 23.2 91.6 a 32.3 dd 181.3 139.8 ... -5.6 d 23.2 ... a ... ... 130.0 183 C13 Figure 1. An ORTEP drawing and labeling scheme for 2 with 40% thermal ellipsoids. have not been investigated, it may be that in this tem- perature range complex 7 undergoes a fluxional process involving a ”flapping” of the bridging p-PPh, ligands without Rh-P bond cleavage, similar to the behavior found for PEt3)2Rh p-PPhz),Rh COD).8 omplex 8 was not spectroscopically characterized but was used in the fol- lowing syntheses as generated. Protonation of the anionic complexes 7 and 8 gave the hydride complexes 2 and 3 (eq 5 and 6). Complex 2 can ; 2 7 Ht - CO)4W-Rh(CO)(PPh3)  5) ‘p H Ph2 2 Ph2 P 8 H* - COW- ’ Rh(COD) 6) ‘p/ H Phz 3 be isolated as a microcrystalline solid, but 3 rapidly transforms into 4 upon workup as detailed below. Both 2 and 3 were also prepared by the direct reaction of the monophosphido reagent 5 with the appropriate metal halides (eq 7 and 8). Both 2 and 3 appear to be iso- structural to the corresponding W-Ir derivatives (CO),- W(pPPh2)zIrH(CO)(PPh3)3 nd (CO),W(@-PPh2),IrH- (COD)4 which have been structurally characterized. This , ganometallic; 1985, 4, 666.- 8) Kreter, P. E.; Meek, D. W. Inorg. Chem. 1983, 22 319.  Binuclear Phosphido-Bridged W-Rh Complexes zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Ph2 P /\ \p H Ph2 zyxwvutsrq  5 zyxwvutsrqpo   zyxwvutsrqpo rans- RhCI(CO)fPPh$2 - CO)4W- Rh(CO)(PPhs) 7) CI Ph2 /\ yP\ 'CRh(C0D) 8) t '/2(COD)Rh Rh(C0D) -- COl4W- \p/ H Phz 3 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA was confirmed for zyxwvutsr   by a complete X-ray diffraction study (Figure 1, see below). Both 2 and 3 show downfield p-PPhz 31P NMR resonances (Table I), implying the presence of W-Rh bonds.6 The lH NMR resonance of the hydride ligand of 2 appears as a temperature-invariant -50 - 0 C), broad (fwhm = 3.4 Hz) triplet at 6 - 12.5 with JP-H = 13.5 Hz. The observed splitting of this resonance is assigned to hydride coupling to the two equivalent bridging phosphorus ligands, but the absence of resolvable hydride coupling to rhodium and the terminal phosphine is sur- prising. The absence of the latter was verified by recording the selectively decoupled 31P(phenyl-'HJ spectrum and observing a 14.1-Hz coupling to the p-PPh, ligand reso- nance but zyxwvutsrqp o phosphorus-hydride coupling to the terminal PPh3 resonance. The crystal structure of 2 (Figure 1) shows the assigned structure to be correct, and we can only suggest that the Rh-H and H-P(PPh3) couplings are 13 Hz and are not resolved. It should be noted that the absence of rhodium-hydride coupling was also observed in HRh(PPh3)4,g nd Darensbourg and co-workers1° ob- served unusually small P-H couplings in hydride com- plexes with trigonal-bipyramidal geometries similar to that of the Rh center in 2 (see below). The lH NMR spectrum of 3 shows the expected doublet of triplets for the hydride ligand at 6 -18.1 with JRh-H and Jp-H = 13.3 Hz. Although complex 3 was sufficiently stable to be spec- troscopically characterized, when exposed to air or upon prolonged standing in solutions under N,, it transformed into the cyclooctenyl complex 4 (eq 9). Complex 4 shows (9) Ph2 P (C0)4W/\Rh(COD) - co)4w- \p/ H 'PPh 2 3 4 a downfield 31P NMR resonance for the equivalent p-PPh, ligands but does not show a hydride lH NMR resonance, consistent with migration of this ligand to the COD ligand. The 'H NMR spectrum also shows resonances attributable to the cyclooctenyl ligand at 6 5.03 (br s) and 3.16 (br s) and several broad multiplets in the 6 0.5-1.5 region. For comparison, the complex Rh(PPh3)2(q3-CsH13), hich has a coordination environment similar to that of 4, shows 'H NMR resonances at 6 5.20, 3.42, and -1.12 (br rn).'O All resonances for 4 are broad due to unresolved lo3Rh-'H and 31P-1H coupling. Phosphido Bridge Cleavage upon Reaction of 2 with Ethylene. The coordination environment of the Rh end of complex 2 superficially resembles the hydroformylation catalyst RhH(CO)(PPh3)3.5 We were thus curious as to how the presence of an adjacent W(CO)4 unit would affect the catalytic properties of the Rh center. Although com- plex 2 does not react with H,, it unfortunately fragments when placed under CO and ethylene atmospheres. An Organometallics, Vol. 6, No. I 1987 103 unresolved mixture of products resulted from the reaction with CO, but ethylene smoothly gave the bridge-cleavage reaction shown in eq 10. Complex 9 can be isolated from (CO)4W Rh(CO)(PPh3) + CH2=CH2 Fh2 22 .c zyxwvutsrqponmlkjihgfedcb \p/ H Ph2 2 p2 (W R h(COI(PPh3) 10) PPh2Et 9 this reaction in modest yield as a microcrystalline yellow solid and appears similar to the corresponding W-Ir and Mo-Rh complexes prepared earlier.3J2 Complex 9 shows separate resonances for the three different phosphorus ligands with the expected coupling pattern (Table I) and with the downfield position of the p-PPh, resonance in- dicating the presence of a W-Rh bond. The mechanism for this reaction presumably involves generation of an ethyl ligand on Rh by insertion of ethylene into the Rh-H bond, followed by reductive coupling of the ethyl and phosphido ligands. Evidence for this suggestion comes from two sources. First, in an attempt to prepare a methyl complex analogous to 2, the anionic complex 7 was treated with CH30Tf. A methyl complex did not result, but instead the PPh2CH3 omplex 10 was formed (eq 11). Presumably the methyl group initially adds to rh2 /\ CCO)W -R h(CO)( PPh3)I- t CHaOTf - 'PA Ph2 7 Ph2 P (C0)4W/-\Rh(CO)(PPh3) (11) I PPhnMe 10 Rh, but with rapid subsequent methyl-phosphido coupling to give the observed product. Also, it was previously found that the relatively stable W-Ir(CH3) complex 11 undergoes a similar reductive coupling to give complex 12 analogous to the W-Rh complex 10 (eq 12).2a These types of Ph2 Fh2 P /\ \ 110 'C (COLW r(CO)(PPh3) - CO)W-Ir(CO)(PPh3) (12) \=' CHI I (9) Dewhist, K. C.; Keim, W.; Reilly, C. A. Inorg. Chem. 1968, 7,546. (10) Ash, C. E.; Delord, T.; Simmons, D.; Darensbourg, M. Y. Or- (11) Reilly, C. A.; Thyret, H. zyxwvuts . Am. Chem. SOC. 1967, 9 144. ganometallics 1986, 5, 17. bhp 11 PPh2CH3 12 bridge-elimination reactions will surely limit the applica- tions of phosphido-bridged complexes in catalytic reactions since many of the catalytic processes of interest involve the formation of metal-carbon bonds at intermediate stages of the reaction, and the formation of a relatively strong P-C bond provides a strong thermodynamic driving force for such bridge degradation. Reaction of Complex 4 with CO PPh3 To Form Complex 2. Complex 4 was observed to rapidly react with PPh3 under 1 atm of CO to form complex 2 in near quantitative yield (eq 13). This reaction presumably proceeds via loss of either 1,3- or 1,5-COD, but no attempt 12) Roberts, D. A. Ph.D. Dissertation, The Pennsylvania State University, 1981.  104 Organometallics, Vol. 6, No. I 1987 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (co)4W- p/ ? h zyxwvutsrqpo   . zyxwv   PPh3 t CO - 4 Phz Ph2 P (C0)4W/-\Rh(CO)(PPh3) (13) \P’ H Ph2 2 was made to identify the organic product. Reaction of Complexes 3 and 4 with CO To Form the Tetranuclear Complex 13. Complex 4 reacts with CO under relatively mild conditions to give the tetranu- clear complex 13, eq 14. Complex 13 has been crystallo- Eh2 r 7 Shulrnan et al. 22 (CO 4W- /‘\Rh& -- ) t CO Ph2 4 Fh2 0 Phn (C0)4W/-\Rh/~\Rh/~W(CO)1 p/ \c/ \p/ (14) Ph2 0 Phz 13 47 ) graphically characterized (Figure 2), and its spectroscopic data are consistent with the determined structure. Noteworthy is the appearance of a single 31P NMR reso- nance at 206 (d), implying equivalent p-PPh, ligands. Complex 13 is quite stable and survives air exposure in both solution and the solid state for prolonged periods. Insight into the mechanism by which complex 13 forms is provided by the analogous reaction of (CO),W(k- PPh2),IrH(COD) with CO. With Ir in place of Rh, a tet- rametallic W21r2 complex is not obtained, but instead complex 15 is isolated in modest yield (eq E ., A complex (CO)4W- ’ Ir(COD) f Co Ph 2 p2 \P/ \H \P ’ 1000 PSI P (CO)4W/JIr(H)(C0)2 t Ph 2 Ph2 15 COD 15) (16) similar to 15 could be an intermediate in the synthesis of 13, and the overall reaction shown in Scheme I is pro- posed. If we consider only the Rh end of these molecules, which is where all the chemistry described herein occurs, the stoichiometry of the proposed conversion of 16 into 14 and then into 13 is similar to established chemistry for HRh(CO)(PPh,), (eq 16).5*13 Indeed, the coordination geometry of the Rh2 portion of 13 is remarkably similar to that found in structurally characterized 1714 zyxwvu see below). -PPha + co HRh(CO)(PPh& cpph HRh(CO)(PPh& E Rh(C0)2(PPh& t t H2 17 (16) 13) Evans, D.; Yagupsky, G.; Wilkinson, G. J. Chem. zyxwvuts OC. A 1968, 14) ingh, P.; Dammann, C. B.; Hodgson, D. J. Inorg. Chem. 1973, 2660. 12, 1335. C56 C156 C96 @ Figure 2. ORTEP diagrams and labeling schemes for the two crystallography independent molecules of 13 drawn with 40 thermal ellipsoids. The isotropic radii for the carbonyl groups 7 and 8 are arbitrary (see Experimental Section). Molecule 1 s on top, and molecule 2 is on the bottom. Scheme I Ph Ph2 Ph2 00 16,x=l,2 14 -2co il+2CO f l13-C0D 13 Reaction of Complex 13 with H2/CO/PPh3 To Yield Complex 2. Complex 13 does not react when stirred for 30 min under 100 psi of H2 pressure in the presence of excess PPh,, but rapid reaction ensues if CO is also present (100 psi, 41 H,/CO) to give complex 2 in near quantitative yield (eq 17). It is interesting that CO is necessary for Ph2 g Pb /p\ / \Rh/p\ (CO)4W h- (CO)4 t H2/CO t 2PPh3 - \p/ \c/ \p/ (4 1 Ph2 0 Ph2 13 Fhz 2(C0)4W/-Rh(CO)(PPh3) (17) \p/ H Ph3 2  Binuclear Phosphido-Bridged W-Rh Complexes Organometallics, Vol. 6 No. 1, 1987 105 Table 11. Crystal Data Collection and Refinement Parameters for zyxwvutsr CO),W W-PP~,)~R~H CO) PP~,) zyxwv 2) and zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA   [(CO)~W(~-PP~~)~R~(~-CO) *XCH~C~~ X 0.5) (13) zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 2 13 Y, deg v, A3 z p(calcd), g cm-3 temp, C cryst dimens, mm radiation diffractometer monochromator data correctns zyxwvutsrq   cm-' max/min trans std reflctns scan method scan speed, deg/min scan range, deg data collected unique data unique data FF2 RwF GOF max shift/error highest peak, final diff map, e A-3 monoclinic triclinic 11.430 (3) 11.580 (2) 19.085 (5) 19.838 (4) 20.738 (6) 22.299 (5) 82.94 (2) 100.80 (2) 79.17 (2) 88.63 (2) 4444 (2) 5857 (2) 4 4 1.59 1.93 (with 22 22 0.26 X 0.26 X 0.31 -1/n P1 '/zCHzClz/fw) 0.12 X 0.20 X 0.24 Mo zyxwvuts a A = 0.71073 A) Nicolet R3 graphite crystal Lp, absorption (empirical) 32.25 48.5 1.21 0.031/0.018 3 std/197 reflctns Wyckoff w 5-20 (var) 10 4 5 29 50 8481 12 864 3 std/197 reflctns (<I% decay) (<1% decay) 4 5 2e 5 43.5 8017 12 334 0.0393 0.0619 5754 [Fo 4(F0)1 6749 [Fo > 3@JI 0.0420 0.0699 1.033 1.234 0.08 0.085 0.59 1.24 this reaction to occur but is not consumed in forming 2. Exposure of solutions of 13 o 1 atm of CO alone gave loss of the vco bands of 13, and new bands grew in at 2040, 2020,1985,1950, and 1930 cm-'. Removal of the solvent and the CO atmosphere gave quantitative reformation of 13. We suggest that 13 adds two CO molecules to form complex 14 (eq 18 and Scheme I) and that it is 14 which reacts with H2/PPh3 o give the observed product. 772 0 Ph2 C / \ / \ ,p (COW p/Rhr/Rhr,W(CO)4 t CO P Ph2 zyxwvutsrqpo   Php 13 14 tructural Characterization of (CO),W(p- PPh,),RhH(CO)(PPh,) 2). An ORTEP drawing of 2 showing the atomic labeling scheme is given in Figure 1, and pertinent crystallographic details are given in Tables I1 and 111. Selected bond lengths and angles are set out in Table IV. The W-Rh bond (2.855 (1) A) is bridged by the two F-PPh, ligands with tungsten further coordinated by four CO's and rhodium by the hydride, CO, and PPh, ligands. The hydride ligand was located and refined. If Table 111. Atomic Coordinates X104) and Isotropic Thermal Parameters (A2 lo3) for 2 X 173.3 (1) -785.7 (5) 558 (2) -1157 (2) -1074 (2) -3058 (5) 2348 (5) 2098 (5) 24 (5) 1552 (6) 1380 (7) -1200 (7) 69 (6) -2677 (7) -3193 (8) -4385 (9) -5032 (9) -4520 (11) -3341 (9) -495 (7) -184 (10) 373 (12) 618 0) 300 (10) -1955 (5) -2224 (7) -277 (8) 2095 (7) 2881 (7) 4047 (8) 4458 (8) 3688 (9) 2520 (7) 122 (7) 567 (8) 165 (10) -672 (9) -1149 (10) -734 (8) -1768 (6) -1434 (8) -1884 (9) -2667 (9) -2981 (9) -2568 8) 280 (7) 910 (9) 1967 (10) 2401 (9) 1785 (8) 743 (7) -1977 (7) -1872 (9) -2586 (12) -3387 (11) -3529 (9) -2818 (7) 149 (75) Y 8820.3 (1) 7515.9 (3) 7597 (1) 8564 (1) 6468 (1) 7379 (4) 8576 (3) 92463 (3) 9142 (3) 10401 (3) 7453 (4) 8661 (4) 9092 (4) 2 784.1 (1) 1115.1 (3) 420 (1) 1596 (1) 1579 (1) 68 (3) 1964 (3) -60 (3) -394 (3) 1207 (3) 454 (4) 1545 (4) 238 (4) 9004 (4) 9833 (4) 8910 (4) 8985 (4) 9213 (5) 9360 (6) 9274 (9) 9054 (7) 8728 (4) 8189 (5) 8300 (7) 8958 (7) 9517 (6) 9398 (5) 7295 (4) 7439 (5) 7215 (6) 6857 (7) 6729 (5) 6945 (4) 7287 (4) 6671 (4) 6406 (5) 6723 (6) 7322 (6) 34 (3) 1049 (3) 1529 (4) 2068 (4) 1999 (6) 1396 (7) 869 (6) 930 (5) 2450 (3) 2881 (4) 3528 (5) 3748 (5) 3331 (5) 2689 (4) 629 (4) 208 (5) 359 (6) 947 (7) 1359 (5) 1200 (4) -426 (3) -621 (4) -1249 (5) -1669 (4) -1498 (4) zyxwvutsrqponmlkjih u 2 34.0 (1) 32.6 (2) 36 (1) 39 (1) 39 (1) 87 (3) 81 (3) 80 (3) 69 (2) 68 (2) 43 (3) 48 (3) 52 (3) 45 (3) 45 (3) 51 (3) 66 (4) 81 (5) 94 (5) 143 (8) 117 (6) 49 (3) 97 (5) 120 (6) 94 (5) 89 (5) 74 (4)O 47 (3) 73 (4) 90 (5) 104 (6) 86 (5) 59 (3) 43 (3) 90 (5) 79 (4) 93 (5) 71 (4) 7610 (5) -871 (4) 75 (4)'' 5806 (4) 989 (4) 46 (3) 5773 (4) 381 (4) 61 (3) 4774 (5) 81 5) 77 (4) 4794 (5) 667 (6) 94 (5) 5301 (4) 1128 (5) 74 (4) 6018 (4) 1987 (4) 46 (3)' 6268 (5) 2576 (4) 73 (4) 5947 (6) 2886 (5) 87 (4)' 5391 (5) 2590 (5) 80 (4)' 5140 (5) 2015 (5) 76 (4) 5447 (4) 1721 (4) 60 (3) 6486 (4) 2210 (4) 50 (3) 5994 (4) 2714 (4) 71 (4) 6043 (6) 3181 (5) 103 (6) 6561 (5) 3178 (5) 94 (5) 7037 (5) 2668 (5) 85 (5) 7005 (4) 2191 (4) 62 (3) 7520 (40) 1611 (39) 72 (28) 5256 (5) -71 (4) 69 (4) Equivalent isotropic U efined as one-third of the trace of the orthogonalised Uij ensor. the W-Rh bond is ignored, the coordination geometry of W is octahedral and that of Rh is trigonal bipyramidal with the hydride ligand trans to CO. The structure is iso- morphous with that of CO),W p-PPhJIrH CO) PPh,) 1) (W-Ir = 2.8764 (6) A)., The only unusual structural fea- ture of 2 is the unrealistically short Rh-H bond length of 1.34 (7) A (Ir-H = 1.60 (8) A in 13). This anomaly is presumably due to the uncertainty in determining hy- drogen atom positions by X-ray diffraction. Structural Characterization of 13. Complex 13 crystallizes in the triclinic space group P1 with two inde- pendent but similar molecules per unit cell. These are , I
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