Cluster Synthesis. 45. Syntheses and Structural Characterizations of

Cluster Synthesis. 46. New Mixed-Metal Complexes of the Layer-Segregated Cluster Pt3Ru6(CO)21(μ3-H)(μ-H)3. Richard D. Adams, Thomas ...
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Organometallics 1996, 14, 2232-2237

2232

Cluster Synthesis. 45. Syntheses and Structural Characterizations of Gold Phosphine Derivatives of the Layer-Segregated Cluster Pt3Ru6(CO)2lOl3-H)Ol-H)3 Richard D. Adams," Thomas S. Barnard, and Jeffrey E. Cortopassi Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208 Received December 29, 1994@ Treatment of the compound P ~ ~ R u ~ ( C ~ ) ~ ~ C ~ - (1) H ) with C U -[BuNIOH H)~ followed by [Au(PEt3)][PF6]yielded two new layer-segregated platinum-ruthenium cluster complexes, Pt3Ru6[Au(PEt3)1(CO)2lCU-H)3 (2; 22% yield) and P~~RU~[AU(PE~~)I~(CO)~~CU~-H)~ (3;5% yield), by the replacement of one and two of the hydride ligands in 1 with Au(PEt3) groupings, respectively, The yield of 3 can be increased to 18%by using larger amounts of [BaNIOH and [Au(PEt3)][PF6].Both compounds were characterized by IR, 'H NMR, and single-crystal X-ray diffraction analyses. Compound 2 was formed from 1 by the substitution of the triply bridging hydride ligand with an Au(PEt3) grouping as a triple bridge on one of the RUB triangles. The structure of the cluster of 3 is similar to that of 2, but the Au(PEt3) groups have assumed triply bridging positions across Ru2Pt triangles on opposite sides of the cluster and the two hydride ligands have adopted triply bridging sites on the two RUBtriangles. Crystal data: for 2, space group P21/a, a = 17.520(2)A, b = 11.867(2)A, c = 20.987(4) A, p = 92.46(1)",2 = 4, 3348 reflections, R = 0.041; for 3,space group P21/c, a = 11.740(2)A, b = 17.351(4) A, c = 25.543(6) A, p = 90.89(2)",2 = 4, 3527 reflections, R = 0.051. prepared by our previously reported procedure.' All other reagents were purchased from Aldrich and were used a s We have recently prepared series of mixed-metal received. All reactions were performed under a nitrogen cluster complexes that contain the first examples of atmosphere unless specified otherwise. Infrared spectra were layer-segregated triangular stacks of platinum comrecorded on a Nicolet 5DXB €TIR spectrophotometer. IH NMR ~ acetylene bined with ruthenium1j2 or ~ s m i u m . An spectra were recorded on a Bruker AM-500 FT-NMR specderivative of the platinum-ruthenium complex Pt3Ru6trometer. Elemental microanalyses were performed by Oneida Research Services Inc., Whitesboro, NY. TLC separations (CO)~~(M-H)~(LQ-H) (1) has been found to exhibit an unusual ability to hydrogenate diphenylacetylene to (2)- were performed in air on Analtech 0.25 mm silica gel 60 A F254 plates. stilbene ~atalytically.~ Synthesis of PtsRus[Au(PEts)l(CO)2lOl-H)3(2) and Pt3Rue[Au(PEt3)]2(CO)21013-H)2(3). A 20.4-mg amount of 1(0.0114 mmol) was dissolved in 20 mL of CHzClz in a 100mL three-necked round-bottom flask. A 7.5-pL amount of [ B m I O H (40 wt % aqueous solution, 1.0 equiv) was added via syringe. The solution was stirred at room temperature for 30 min. A solution of [Au(PEt3)][PFs]was prepared by stirring 4.0 mg of Au(C1)PEtz (0.0114 mmol) and 4.2 mg of TlPF6 (0.0120 mmol) in 5 mL of CHzClz for 5 min and then filtering to remove TlC1. This solution was then added to the previously In an effort to explore the unusual properties of these prepared solution of 1 plus OH-; see above. The mixture was layer-segregatedmixed-metal cluster complexes further, stirred a t room temperature for 30 min, and the solvent was we have prepared the derivatives Pt3Rus[Au(PEt3)1then removed. The residue was transferred to TLC plates (2) and P~~RU~[AU(PE~~)I~(CO)~~(M~-H)~ (3) (C0)21(M-H)3 using a minimum of CHzCl2 and then separated by using a by the replacement of one and two of the hydride ligands hexane/CHzClz (1/1) solvent mixture. This yielded the followin 1with Au(PEt3)groupings. The syntheses and charing, in order of elution: a dark brown band of Pt3R~[Au(PEt3)1acterizations of these new compounds are reported here. (CO)zl@-H)3(2; 5.2 mg, 22%) and a brown band of P t ~ R u d A u IR for 2: (v(CO),cm-'; ( P E ~ ~ ) I Z ( C O ) ~(3; ~ ( 1.5 ~ ~ mg, - H )5%). ~ Experimental Section in hexane): 2094 (w), 2054 (s, sh), 2049 (vs), 2035 (m), 2021 (w), 1986 (w). 'H NMR for 2 (6; in CDC13): 2.02 (dq, 6H, CHZ, General Procedures. Reagent grade solvents were stored =7.7~Hz, 'JP-H = 16.6 HZ), 1.23 (dt, 9H, CH3, 3 J ~ = - ~ over 4 A molecular sieves. P ~ ~ R U ~ ( C O ) Z ~ ( ~ - H(1) ) ~was @~-H) 3 J ~ 7.6 Hz, 3 J p - ~= 18.2 Hz), -17.32 (s, 3H, RuH, ' J p t - ~ = 39.1 @Abstractpublished in Advance ACS Abstracts, April 1, 1995. Hz). Anal. Calcd (found) for 2: C, 15.45 (15.13);H, 0.86 (1.02). (l)Adams, R. D.; Li, Z.; Wu, W.; Yamamoto, J. Organometallics IR for 3 (v(CO), cm-'; in hexane): 2081 (w), 2049 (s), 2044 (s, 1994, 13, 2357. sh), 2037 (vs), 2027 (s), 1982 (w, br). lH NMR for 3 ( 6 ;in CD2(2) Adams, R. D.; Li, 2.; Wu, W. Organometallics 1992, 11, 4001. (3) (a)Adams, R. D.; Lii, J.-C.; Wu, W. Inorg. Chem. 1991,30,3613. Clz): 2.01 (dq, 18H, CHz, 3 J ~ = 7.6 - ~ Hz, 'JP-H = 9.2 Hz), 1.21 (b) Adams, R. D.; Lii, J.-C.; Wu, W. Inorg. Chem. 1992, 31, 2556. ( c ) (dt, 12H, CH3, 3 J ~ =7.6~Hz, 3 J p - ~= 18.2 HZ), -18.63 (S, Adams, R. D.; Lii, J.-C.; Wu, W. Inorg. Chem. 1991, 30, 2257. 2H, RuH). Anal. Calcd (found) for 3: C, 16.43 (16.00); H, 1.34 (4) Adams, R. D.; Barnard, T. S.; Li, Z.; Wu, W.; Yamamoto, J. J. (1.33). Am. Chem. Soc. 1994,116, 9103.

Introduction

0276-7333/95/2314-2232$09.00/0

0 1995 American Chemical Society

Cluster Synthesis

Table 1. Crystal Data for Compounds 2 and 3

Organometallics, Vol. 14, No. 5, 1995 2233

Table 2. Positional Parameters and B(eq) Values (A2)for RusPts[Au(PEta)l(C0)2101-H)3(2)

2 3 atom X AUP~~RU&'OZIC~~HI~ AUZP~~RU~P~O~IC~~H~Z 2098.06 2412.17 Au(1) 0.64579(6) monoclinic monoclinic R(1) 0.79581(5) Pt(2) 0.82759(5) 11.740(2) 17.520(2), a (A) Pt(3) 0.70509(5) 17.351(4) 11.867(2) Ru(1) 0.7956(1) b (A) 25.542(6) 20.987(4) Ru(2) 0.6507(1) c (A) 90 90 a (deg) Ru(3) 0.6876(1) 90.89(2) 92.46( 1) /3 (deg) Ru(4) 0.8255(1) 90 90 y (deg) Ru(5) 0.7888(1) 5202(2) 4359(1) Ru(6) 0.9306(1) v (A31 P21/~(NO. 14) space group P21/u (NO. 14) P(1) 0.5856(4) 4 4 z O(10) 0.813(1) 3.20 3.08 O(11) 0.966(1) ecalc (g/cm3) 155.0 p(Mo Ka)(cm-') 150.4 O(12) 0.781(1) 20 20 temp ("C) O(13) 0.827(1) 43.0 43.0 O(20) 0.914(1) 28,,, (deg) 3527 no. of obs rflns 3348 O(21) 0.604(1) O(22) 0.635(1) (1'30(0) 2.02 2.16 goodness of fit O(23) 0.479(1) O(30) 0.544(1) (GOF) 0.051; 0.046 residuals? R; Rw 0.041; 0.034 O(31) 0.708(2) 0.37 max shiftlerror 0.25 O(32) 0.518(1) O(33) 0.701(1) O(41) 0.906(1) O(42) 0.676(1) O(43) 0.872(1) O(51) 0.627(1) O(52) 0.848(1) O(53) 0.769(1) O(61) 0.979(1) O(62) 1.0334(9) O(63) 1.054(1) C(10) 0.807(1) C(11) 0.900(1) C(12) 0.781(1) C(13) 0.810(1) C(20) 0.881(1) C(21) 0.625(1) C(22) 0.640(1) C(23) 0.546(1) C(30) 0.605(1) C(31) 0.702(1) C(32) 0.576(2) C(33) 0.696(1) C(41) 0.874(1) C(42) 0.731(1) C(43) 0.853(2) C(51) 0.685(1) C(52) 0.820(2) C(53) 0.778(1) C(61) 0.957(2) C(62) 0.990(1) C(63) 1.008(1) C(71) 0.588(6) C(72) 0.597(2) C(73) 0.484(2) C(74) 0.443(2) C(75) 0.594(5) C(76) 0.661(2)

formula fw cryst syst lattice params

I

Y

-0.08624(8) 0.07940(8) 0.09092(8) -0.1276(2) -0.1143(1) 0.0767(2) 0.2519(2) 0.0629(1) 0.0502(1) -0.2343(7) -0.332(1) -0.162(2) -0.382(2) -0.101(2) 0.143(2) -0.129(2) -0.370(1) -0.084(2) 0.179(2) 0.097(2) 0.109(2) 0.334(1) 0.437(2) 0.384( 1) 0.371(1) 0.126(1) 0.123(1) -0.174(1) -0.194(1) 0.087(2) 0.123(1) -0.240(2) -0.148(2) -0.286(2) -0.111(2) 0.119(2) -0.116(2) -0.277(2) -0.089(2) 0.144(2) 0.084(3) 0.098(2) 0.239(2) 0.366(2) 0.326(2) 0.318(2) 0.099(2) O.lOO(2) -0.088(2) -0.107(2) 0.073(2) 0.093(2) -0.38(1) -0.447(4) -0.236(3) -&147(3) -0.195(7) -0.152(3)

2

B(ed

0.14703(5) 0.32937(5) 0.25136(5) 0.31817(5) 0.2027(1) 0.2809(1) 0.1894(1) 0.3486(1) 0.4377(1) 0.3608(1) 0.0632(4) 0.358(1) 0.225(1) 0.188( 1) 0.061(1) 0.137(1) 0.419(1) 0.269(1) 0.246(1) 0.330( 1) 0.046( 1) 0.157(1) 0.195( 1) 0.426(1) 0.349(1) 0.229(1) 0.4717(8) 0.568(1) 0.4862(9) 0.374(1) 0.248( 1) 0.4588(9) 0.350(1) 0.218(2) 0.194( 1) 0.114(1) 0.180(1) 0.368(1) 0.271(1) 0.256(1) 0.328(1) O.lOl(1) 0.174(1) 0.194(1) 0.401(1) 0.347(1) 0.270(1) 0.454(1) 0.519(1) 0.460( 1) 0.361(2) 0.288(1) 0.424(1) 0.053(6) 0.102(2) 0.059(2) 0.072(2) -0.010(5) -0.039(2)

This solution was then added to the above reaction solution. The resulting solution was stirred a t room temperature for 30 min, and the solvent was removed. The residue was transferred t o TLC plates using a minimum amount of CHZFigure 1. ORTEP diagram of P~~Ru~[Au(PE~~)I(CO)~~~~Cl2. The product was isolated using a hexane/CHzClz (1/1) HI3 (2) showing 40% probability thermal ellipsoids. solvent mixture to yield a dark brown band of 3 (4.7 mg, 18%), Improved Synthesis of PtsRus[Au(PEts)]a(CO)a~~s-H)a and no 2 was obtained. Crystallographic Analyses. Crystals of 2 suitable for (3). An 18.9-mgamount of 1(0.0106 mmol) was dissolved in X-ray diffraction analysis were grown from a solution in a 20 mL of CHzClz in a 50-mL three-necked flask. A 14.6-pL dichloromethanehexane (111)solvent mixture by slow evapoamount of [BudNIOH (40 wt % aqueous solution, 2.1 equiv) ration of t h e solvent at 25 "C. Crystals of 3 suitable for X-ray was added via syringe. The solution was stirred at room diffraction analysis were grown from a solution in a dichlotemperature for 30 min. An IR spectrum of the solution taken romethaneheptane (1/1) solvent mixture by slow evaporation at this time showed a single broad absorption at 2006 cm-l. A of the solvent at 25 "C. The crystals used for intensity solution of [Au(PEts)l[PF6l was prepared by stirring 11.0 mg measurements were mounted in thin-walled glass capillaries. of Au(CUPEt3 (0.031 mmol) and 22.0 mg of TlPF6 (0.063 mmol) Diffraction measurements were made on a Rigaku AFC6S in 7 mL of CHzCl2 for 5 min and t h e n filtering to remove TlC1.

2234 Organometallics, Vol. 14, No. 5, 1995

Adams et al.

Table 3. Intramolecular Distances for 2" Au(l)-Ru(l) Au(l)-Ru(2) Au(l)-Ru(3) Au(l)-P(l) Pt(l)-Pt(2) Pt(l)-Pt(3) Pt(l)-Ru(l) Pt(l)-Ru(2) Pt(1)-Ru(5) Pt(l)-Ru(6) Pt(l)-C(lO) Pt(2)-Pt(3) Pt(2)-Ru( 1) Pt(2)-Ru(3) Pt(2)-Ru(4) Pt(2)-R~(6) Pt(2)-C(20) Pt(3)-Ru(2) Pt(3)-Ru(3) Pt(3)-Ru(4) Pt(3)-Ru(5) Pt(3)-C(30) Ru(l)-Ru(2) Ru(l)-Ru(3) Ru( 1)-C( 11) R~(l)-C(12)

2.833(2) 2.828(3) 2.840(2) 2.285(8) 2.633(1) 2.640(1) 2.703(3) 2.717(2) 2.888(2) 2.915(2) 1.88(2) 2.617(1) 2.710(2) 2.726(2) 2.891(2) 2.880(2) 1.85(3) 2.718(2) 2.713(2) 2.896(2) 2.870(2) 1.88(2) 3.085(3) 3.080(3) 1.85(2) 1.90(3)

Ru(l)-C(13) Ru(2)-Ru(3) R~(2)-C(21) R~(2)-C(22) R~(2)-C(23) R~(3)-C(31) Ru(3)-C(32) R~(3)-C(33) Ru(4)-Ru(5) Ru(4)-Ru(6) Ru(4)-C(41) Ru(4)-C(42) Ru(4)-C(43) Ru(4)-H(l) Ru(4)-H(3) Ru(5)-Ru(6) R~(5)-C(51) Ru(5)-C(52) Ru(5)-C(53) Ru(5)-H(l) Ru(5)-H(2) Ru(6)-C(61) R~(6)-C(62) Ru(6)-C(63) Ru(6)-H(2) Ru(6)-H(3)

1.91(3) 3.059(3) 1.89(3) 1.95(3) 1.92(2) 1.88(3) 1.98(3) 1.94(3) 3.008(3) 3.025(3) 1.91(3) 1.87(2) 1.91(3) 1.62 1.78 3.024(3) 1.91(2) 1.83(3) 1.86(2) 1.71 1.91 1.92(3) 1.91(3) 1.93(3) 1.82 2.01

a Distances are in angstroms. Estimated standard deviations in the least significant figure are given in parentheses.

automatic diffractometer by using graphite-monochromated Mo Ka radiation. Unit cells were determined from 25 randomly selected reflections obtained by using t h e AFC6 automatic search, center, index, and least-squares routines. Crystal data, data collection parameters, and results of the analyses a r e listed i n Table 1. All d a t a processing was performed on a Digital Equipment Corp. VAXstation 3520 computer by using the TEXSAN structure-solving program library obtained from the Molecular Structure Corp., The Woodlands, TX. Lorentzpolarization ( L p ) and absorption corrections were applied to t h e d a t a i n each analysis. Neutral atom scattering factors were calculated by t h e standard procedure^.^^ Anomalous dispersion corrections were applied to all non-hydrogen atoms.5b Both structures were solved by a combination of direct methods (MITHRIL) and difference Fourier syntheses. Full-matrix least-squares refinements minimized t h e function Chklw( iFol - iFc1)2,where w = l/o(F)2,u ( F )= u(FO2)/2F,,, and a(Fo2)= [u(1,,,)2+(0.02Z,,~)z11'2/Lp. For all four analyses, t h e positions of t h e hydrogen atoms on t h e ligands were calculated by assuming idealized geometry, C - H = 0.95 A. Compound 2 crystallized i n t h e monoclinic crystal system. The space group P21/a was established on t h e basis of t h e patterns of systematic absences observed in the data. All nonhydrogen atoms were refined with anisotropic thermal parameters. The positions of t h e three hydride ligands were obtained i n difference Fourier syntheses. They were partially refined but would not converge and were therefore fixed on t h e final cycles of refinement. The positions of t h e hydrogen atoms on t h e ethyl groups were calculated by assuming idealized geometries and C-H = 0.95 A. Their scattering contributions were added to t h e structure factor calculations, but their positions were not refined. Compound 3 crystallized i n the monoclinic crystal system. The space group P2Jc was established on t h e basis of the patterns of systematic absences observed i n t h e data. Except for t h e carbon atoms of t h e ethyl groups, all non-hydrogen atoms were refined with anisotropic thermal parameters. The carbon atoms of t h e ethyl groups exhibited considerable disorder. They were refined partially with isotropic thermal parameters and were subsequently added as fixed contributions in the final cycles using t h e partially refined values. Reasonable positions of the two hydride ligands were obtained ( 5 )(a) International Tables for X-ray Crystallography; Kynoch Press: Birmingham, England, 1975; Vol. IV, Table 2.2B, pp 99-101. (b) Ibid., Table 2.3.1, pp 149-150.

Table 4. Intramolecular Bond Angles for 2a Ru(l)-A~(l)-Ru(2) 66.05(6) Ru( 1)-Au( 1) - R u ( ~ ) 65.78(6) Ru(l)-Au(l)-P(l) 137.5(2) R u ( ~ ) - A u ( ~ ) - R u ( ~ )65.33(6) Ru(2)-Au( 1)-P( 1) 144.6(2) Ru(3)-Au(l)-P(l) 141.3(2) Pt(2)-Pt(l)-Pt(3) 59.52(3) Pt(2)-Pt(l)-Ru(l) 61.02(5) Pt(2)-Pt(l)-R~(2) 94.49(6) Pt(2)-Pt(l)-R~(5) 92.83(5) Pt(2)-Pt(l)-R~(6) 62.31(5) Pt(3)-Pt(l)-Ru(l) 94.68(5) Pt(S)-Pt(l)-Ru(Z) 60.95(5) Pt(3)-Pt(l)-R~(5) 62.37(5) Pt(3)-Pt(l)-Ru(6) 93.25(5) Ru(l)-Pt(l)-Ru(2) 69.39(7) Ru(l)-Pt(l)-Ru(B) 152.52(7) Ru(l)-Pt(l)-R~(6) 106.87(7) Ru(2)-Pt(l)-Ru(5) 107.40(6) Ru(2)-Pt(l)-Ru(6) 152.68(6) Ru(5)-Pt(l)-Ru(6) 62.81(6) Pt(l)-Pt(2)-Pt(3) 60.38(4) Pt(l)-Pt(2)-Ru(l) 60.77(6) Pt(l)-Pt(2)-Ru(3) 94.49(6) Pt(l)-Pt(2)-R~(4) 94.61(6) Pt(l)-Pt(2)-R~(6) 63.66(5) Pt(S)-Pt(2)-Ru(l) 95.05(6) Pt(3)-Pt(2)-R~(3) 60.98(5) Pt(3)-Pt(2)-R~(4) 63.21(5) Pt(3)-Pt(2)-R~(6) 94.55(6) Ru(l)-Pt(2)-Ru(3) 69.04(6) Ru(l)-Pt(2)-Ru(4) 154.02(7) Ru(l)-Pt(2)-Ru(6) 107.68(6) R u ( ~ ) - P ~ ( ~ ) - R u (107.84(6) ~) R u ( ~ ) - P ~ ( ~ ) - R u (154.04(7) ~) R u ( ~ ) - P ~ ( ~ ) - R u ( ~63.21(6) ) Pt(l)-Pt(3)-Pt(2) 60.1l(4) Pt(l)-Pt(S)-Ru(2) 60.92(5) Pt(l)-Pt(3)-R~(3) 94.64(6) Pt(l)-Pt(S)-Ru(4) 94.34(5) Pt(l)-Pt(3)-R~(5) 63.05(5) Pt(2)-Pt(3)-R~(2) 94.84(6) Pt(2)-Pt(3)-R~(3) 61.49(5) Pt(2)-Pt(3)-Ru(4) 63.02(5) Pt(2)-Pt(3)-R~(5) 93.56(5) R u ( ~ ) - P ~ ( ~ ) - R u ( ~68.57(7) ) R u ( ~ ) - P ~ ( ~ ) - R u (153.80(6) ~) R u ( ~ ) - P ~ ( ~ ) - R u (107.87(6) ~) R u ( ~ ) - P ~ ( ~ ) - R u (108.07(7) ~) Ru(3)-Pt(3)-Ru(5) 153.53(6)

Ru(4)-Pt(3)-Ru(5) 62.88(6) Au( 1)-Ru( 1)-Pt(1) 112.31(8) A~(l)-Ru(l)-Pt(2) 112.75(7) Au(l)-Ru(l)-Ru(2) 56.91(6) Au(l)-Ru( l)-Ru( 3) 57.23(5) Pt(l)-R~(l)-Pt(2) 58.22(5) Pt(Y.)-Ru(l)-Ru(2) 55.52(6) Pt(l)-Ru(l)-Ru(3) 85.50(7) Pt(2)-Ru(l)-Ru(2) 85.12(7) Pt(2)-Ru(l)-Ru(3) 55.73(6) Ru(2)-Ru(l)-Ru(3) 59.50(6) Au(l)-Ru(Z)-Pt(l) 112.02(8) Au(l)-Ru(2)-Pt(3) 112.88(7) Au(l)-Ru(2)-Ru(l) 57.05(6) A u ( ~ ) - R u ( ~ ) - R u ( ~ )57.53(6) Pt(l)-R~(2)-Pt(3) 58.13(5) Pt(l)-Ru(2)-Ru(l) 55.09(6) Pt(l)-Ru(2)-Ru(3) 85.68(6) Pt(3)-Ru(B)-Ru(l) 85.00(6) Pt(3)-Ru(2)-Ru(3) 55.63(6) Ru(l)-Ru(2)-Ru(3) 60.18(6) Au(l)-Ru(B)-Pt(a) 112.01(7) Au(l)-Ru(3)-Pt(3) 112.65(8) Au(l)-Ru(3)-Ru(l) 56.99(6) A u ( ~ ) - R u ( ~ ) - R u ( ~ 57.14(6) ) Pt(2)-Ru(3)-Pt(3) 57.53(5) Pt(2)-Ru(3)-Ru(l) 55.23(5) Pt(2)-Ru(3)-Ru(2) 85.34(7) Pt(3)-Ru(3)-Ru(l) 85.17(7) Pt(3)-Ru(3)-Ru(2) 55.79(6) R u ( ~ ) - R u ( ~ ) - R u ( ~ )60.32(6) Pt(2)-Ru(4)-Pt(3) 53.77(4) Pt(2)-Ru(4)-Ru(5) 85.43(6) Pt(2)-Ru(4)-Ru(6) 58.22(6) Pt(3)-Ru(4)-Ru(5) 58.14(5) P ~ ( ~ ) - R u ( ~ ) - R u ( ~86.09(6) ) R u ( ~ ) - R u ( ~ ) - R u ( ~ )60.17(6) Pt(l)-Ru(5)-Pt(3) 54.58(5) Pt(l)-Ru(5)-Ru(4) 87.13(7) Pt(l)-Ru(5)-Ru(6) 59.04(6) Pt(3)-Ru(5)-Ru(4) 58.98(6) P ~ ( ~ ) - R u ( ~ ) - R u ( ~86.57(7) ) R u ( ~ ) - R u ( ~ ) - R u ( ~ 60.20(6) ) Pt(l)-Ru(G)-Pt(2) 54.03(4) Pt(l)-Ru(G)-Ru(4) 86.31(6) Pt(l)-Ru(G)-Ru(G) 58.14(5) Pt(2)-Ru(6)-Ru(4) 58.57(6) P ~ ( ~ ) - R u ( ~ ) - R u ( ~85.32(6) ) R u ( ~ ) - R u ( ~ ) - R u ( ~ )59.63(6) M-C-0 (av) 173(3)

Angles are in degrees. Estimated standard deviat.ions in the least significant figure are given in parentheses. from difference Fourier maps. They were refined to a suitable convergence on their positional parameters using a fixed isotropic thermal parameter. The hydrogen atoms on the ethyl groups were ignored i n this analysis.

Results and Discussion Although the hydride ligands in many metal compounds are often regarded as hydride (H-) donors, it is also well-known that the hydride ligands in many metal carbonyl complexes can often be abstracted as the positively charged ion H+ by suitable bases.6 The conjugate bases are metal carbonyl anions, and such anions are widely used for the synthesis of new organometallic ~omplexes.~ In this study we have used the tetrahydride complex 1 to synthesize some Au(PEt8)substituted derivatives of 1 by treatment of 1 with a series of [Bun4N10H and [(PEt3)Aul[PF61. Infrared (6) (a) Pearson, R. G.; Ford, P. C. Comments Inorg. Chem. 1982, 1 , 279. (b) Walker, H. W.; Kresge, C. T.; Ford, P. C.; Pearson, R. G. J . Am. Chem. SOC.1979,101, 7428. (7) King, R. B. Ace. Chem Res. 1970,3 , 182.

Organometallics, Vol. 14,No. 5, 1995 2235

Cluster Synthesis

Figure 2. ORTEP diagram of P ~ ~ R U ~ [ A U ( P E ~ ~ ) I ~ (3) ( Cshowing O ) ~ ~ ~40% ~ - Hprobability )~ thermal ellipsoids. spectra of solutions of 1 treated with 1 and 2 equiv of [Bun4N10H show a progressive shift of the dominant absorption in 1 a t 2067 cm-l to 2020 and 2006 cm-l, respectively. This shift to lower frequency is indicative of a greater back-bonding to the CO ligands and is consistent with the formation of negatively charged cluster species. The addition of [(PEt3)Aul[PFsl t o solutions of 1 treated with 1.0 equiv [Bun4N10H provided two new gold-containing complexes after chromatographic work(2; 22% yield) and P t 3 up: P~~R~~[AU(PE~~)I(CO)Z~~~-H)~ RU~[A~(PE~~)IZ(CO)~~~~~-H)Z (3;5%yield). The yield of 3 could be increased t o 18%at the expense of 2 when larger amounts of [Bun4N10Hwere used in the initial treatment of 1. Both products were characterized by a combination of IR, lH NMR, and single-crystal X-ray diffraction analyses. An ORTEP diagram of the molecular structure of 2 is shown in Figure 1. Final atomic positional parameters are listed in Table 2, and selected intramolecular distances and angles are listed in Tables 3 and 4. The molecule is structurally very similar t o that of 1. The

c

Et'&El

cluster consists of a stacked layer-segregated arrangement of six ruthenium and three platinum atoms with the platinum triangle in the center. Each metal triangle is rotated 60" from that of its nearest neighbor, which produces a staggered arrangement of the three triangles. This differs from that of the stacked Pt3

triangular clusters [Pt3(co)6In2- ( n = 2-5) that were studied by Chini and Dahl.8 The three hydride ligands are chemically equivalent and exhibit a single resonance in the lH NMR spectrum at 6 -17.32 ppm with the appropriate long-range coupling to platinum, 2 J p t - ~= 39.1 Hz. They were located and partially refined in the X-ray analysis. They occupy bridging positions across each of the three Ru-Ru bonds on one of the Ru3 triangles. The associated Ru-Ru bond distances are elongated (Ru(4)-Ru(5) = 3.008(3) A, Ru(4)-Ru(6) = 3.025(3)A, and Ru(5)-Ru(6) = 3.024(3)A) as expected. Similar elongation of the hydride-bridged Ru-Ru bonds was observed in 1 (Ru(4)-Ru(5) = 3.002(2) 8,Ru(4)Ru(6) = 3.024(2)A, and Ru(WRu(6)= 3.033(2)A1.l The gold atom is bonded equally to all three ruthenium atoms of the other RUBtriangle (Ru(l)-Au = 2.833(2) A, Ru(21-A~ = 2.828(3) A, and Ru(31-A~ = 2.840(2) A). These distances are similar t o those that have been reported for a variety of other gold-ruthenium cluster c o m p l e ~ e s . ~In- ~1~the site of the gold atom is occupied by a triply bridging hydride ligand. The platinumplatinum and platinum-ruthenium distances in 2 are similar to those found in 1. The PtS triangle does not lie midway between the two RUBtriangles but is positioned about 0.23 A closer to the Au-bridged triangle (2.15 A) than to the hydride-containing triangle (2.38 A). In 1 the Pt3 triangle was found to lie 0.23 A closer to the Ru3 triangle that contained the single hydride ligand (2.15 A vs 2.38 Ah1 As found in 1, each ruthenium atom contains three linear terminal carbonyl ligands and each platinum atom has only one linear terminal carbonyl ligand. Overall, the molecule contains a total of 124 valence electrons about the 9 P t 3 Rug atoms (gold excluded), which is precisely the (8) (a) Longoni, G.; Chini, P. J.Am. Chem. SOC.1976,98, 7225.(b) Calabrese, J. C.; Dahl, L. F.; Chini, P.; Longoni, G.; Martinengo, S.J. Am. Chem. SOC.1974,96,2614. (9) Salter, I. D. Adu. Orgunomet. Chem. 1989,29,249. (10)Orpen, A. G.; Salter, I. D. Organometallics 1991,10, 111 and references therein. (11)Bruce, M. I.; Nicholson, B. K. Organometallics 1984,3, 101.

2236 Organometallics, Vol. 14,No.5, 1995

Table 5. Positional Parameters and B(eq) Values (Az>for RuePt3CAu(PEt3)lz(CO)zlH~(3) atom

X

0.5489(1) 0.9113(1) 0.7469( 1) 0.7244(1) 0.7470(1) 0.5623(2) 0.5328(2) 0.5475(2) 0.9285(2) 0.9273(2) 0.9465(2) 0.480(1) 0.956(1) 0.817(2) 0.692(3) 0.330(2) 0.534(3) 0.645(2) 0.454(3) 0.290(2) 0.6 19(2) 0.738(2) 0.403(3) 0.373(3) 0.654(2) 0.838(3) 0.968(2) 1.174(3) 1.150(2) 0.803(2) 1.016(3) 1.044(3) 1.167(3) 0.862(3) 0.788(3) 0.641(4) 0.418(3) 0.542(3) 0.678(3) 0.482(4) 0.381(3) 0.593(3) 0.742(3) 0.459(4) 0.441(3) 0.621(3) 0.868(3) 0.949(3) 1.081(4) 1.068(3) 0.850(3) 0.983(3) 1.003(4) 1.089(4) 0.885(3) 0.5628 0.6100 0.3191 0.2886 0.5156 0.4696 0.9407 0.8963 1.0968 1.1929 0.8638 0.8162 0.99(2) 0.49(2)

Y 0.22774(7) 0.12628(7) 0.15752(6) 0.10216(6) 0.00624(6) 0.0663(1) 0.1739(1) 0.0042(1) 0.0152(1) 0.1891(1) 0.0758(1) 0.3254(5) 0.1484(6) 0.280(1) 0.102(2) 0.101(1) -0.096(1) 0.092(2) 0.204(2) 0.212(2) 0.340(1) -0.159(1) 0.026(2) -0.104(1) -0.134(1) -0.064(1) -0.141(1) 0.011(2) 0.218(2) 0.309(1) 0.312(2) 0.187(2) -0.013(2) -0.026(2) 0.233(2) 0.094(2) 0.089(2) -0.036(2) 0.099(2) 0.186(3) 0.199(2) 0.273(2) -0.093(2) 0.022(3) -0.064(2) -0.080(2) -0.029(2) -0.080(2) 0.014(2) 0.202(2) 0.261(2) 0.263(2) 0.146(2) 0.019(2) 0.015(2) 0.4089 0.4448 0.3385 0.3727 0.3388 0.2716 0.0550 0.0837 0.1965 0.1303 0.2231 0.2788 O.lO(1) 0.08(1)

z

0.40865(6) 0.19464(6) 0.36119(5) 0.26502(5) 0.34596(6) 0.3983(1) 0.3035(1) 0.2885(1) 0.2763(1) 0.2964(1) 0.3841(1) 0.4582(5) 0.1106(4) 0.439(1) 0.497(1) 0.442(1) 0.437(1) 0.153(1) 0.196(1) 0.335(1) 0.303(1) 0.378(1) 0.197(1) 0.333(1) 0.240(1) 0.179(1) 0.323(1) 0.240(2) 0.240(1) 0.232(1) 0.369(1) 0.460(2) 0.390(1) 0.471(2) 0.411(1) 0.460(2) 0.428(2) 0.416(1) 0.195(1) 0.233(2) 0.326(1) 0.304(1) 0.361(1) 0.235(2) 0.316(2) 0.259(2) 0.212(2) 0.306(2) 0.252(2) 0.257(2) 0.257(2) 0.346(2) 0.429(2) 0.387(2) 0.435(2) 0.4607 0.4220 0.4383 0.4400 0.5305 0.5469 0.0784 0.0205 0.0981 0.1182 0.0733 0.0923 0.32(1) 0.321(9)

number predicted by the polyhedral skeletal electron pair theory for an arrangement of 9 metal atoms in a face-shared bioctahedral structure.12 (12)Mingos, D. M. P.; May, A. S. In The Chemistry ofMetul Cluster Complexes; Shriver, D. F., Kaesz, H. D., Adams, R. D., Eds.; VCH: New York, 1990; Chapter 2.

Adams et al.

Table 6. Intramolecular Distances for 3" Au(l)-Pt(l) Au( l)-Ru( 1) Au( 1)-Ru( 2) Au(l)-P(l) Au(2)-Pt(2) Au(~)-Ru(~) Au(~)-Ru(~) Au(2)-P(2) Pt(1)-Pt(2) Pt(l)-Pt(3) Pt(1)-Ru( 1) Pt(l)-Ru(%) Pt(l)-R~(5) Pt(l)-Ru(6) Pt(l)-C(lO) F't(2)-Pt(3) Pt(2)-R~(2) Pt(2)-Ru(3) Pt(2)-R~(4) Pt(2)-Ru(5) Pt(2)-C(20) Pt(S)-Ru(l) Pt(3)-Ru(3) Pt(3)-Ru(4) Pt(3)-R~(6) Pt(3)-C(30) Ru(1)-Ru( 2) Ru( l)-Ru(3) Ru(l)-C(11)

2.907(2) 2.818(3) 2.847(3) 2.274(9) 2.889(2) 2.844(3) 2.821(3) 2.25(1) 2.647(2) 2.654(2) 2.857(3) 2.908(3) 2.763(3) 2.793(3) 1.89(3) 2.664(2) 2.764(3) 2.756(3) 2.843(3) 2.921(3) 1.85(4) 2.768(3) 2.744(3) 2.802(3) 2.797(3) 1.76(3) 3.071(4) 3.006(4) 1.88(5)

Ru(l)-C(12) Ru(l)-C(13) Ru(l)-H(2) Ru(2)-Ru(3) Ru(2)-C(21) Ru(2)-C(22) Ru(2)-C(23) Ru(2)-H(2) Ru(3)-C(31) Ru(3)-C(32) Ru(3)-C(33) Ru(3)-H(2) Ru(4)-Ru(5) Ru(4)-Ru(6) R~(4)-C(41) Ru(4)-C(42) Ru(4)-C(43) Ru(4)-H(l) Ru(5)-Ru(6) Ru(5)-C(51) Ru(5)-C(52) R~(5)-C(53) Ru(5)-H( 1) Ru(6)-C(61) Ru(6)-C(62) Ru(6)-C(63) Ru(G)-H(l) 0-C (av)

1.91(4) 1.85(3) 2.2(2) 2.973(3) 1.89(5) 1.93(3) 1.86(3) 1.7(2) 1.74(4) 1.87(4) 1.87(3) 1.8(2) 3.061(3) 2.953(4) 1.93(4) 1.83(3) 1.90(4) 2.0(2) 2.986(4) 1.97(4) 1.82(4) 1.91(4) 1.9(2) 1.79(5) 1.94(4) 1.84(4) 1.7(2) 1.15(4)

a Distances are in angstroms. Estimated standard deviations in the least significant figure are given in parentheses.

A n ORTEP diagram of the molecular structure of 3 is shown in Figure 2. Final atomic positional parameters are listed in Table 5, and selected intramolecular distances and angles are listed in Tables 6 and 7. This molecule also possesses the stacked arrangement of the six ruthenium and three platinum atoms with the three platinum atoms as a triangle sandwiched between two triruthenium triangles. There are two AuPEt3 groups that occupy triply bridging sites on PtRuz triangles on opposite sides of the Pt3 triangle. The gold-ruthenium distances are similar to those found in 2 and other gold= 2.818ruthenium cluster c o m p l e ~ e s (Ru(1)-Au(1) ~-~~ =)2.844(3) (3) A, Ru(2)-Au(l) = 2.847(3)A, R u ( ~ ) - A u ( ~ A, and Ru(5)-Au(2) = 2.821(3)A). The gold-platinum distances are slightly longer than the gold-ruthenium distances (Au(1)-Pt(1) = 2.907(2) A and Au(2)-Pt(2) = 2.889(2)A). These distances are significantly longer than those found for gold-capped Pt3 clusters, such as [ A U P ~ ~ ~ ~ - C O ) ~ ( P P (Au-Pta, ~ ~ ) ~ ] [=N2.84 O ~ IA), ~~~ [AUPt301-CO)3{P(C6H11)3}41[PF6113b (Au-Ptav = 2.758(5) A), [AuPt301-CO)zCu-S02){P(CsH11)3}41[PF6113c (AuP t a V = 2.757(1)A), and [AUPt30L-C1)01-SO2)2{P(CsH11)3}3{ P ( C ~ H ~ - ~ - F ) ~ ) I [(Au-Ptav P F G I = 2.769(1) A).13c The longer distances in 3 may be produced by steric effects, since each of the gold-bound platinum atoms have seven neighboring metal atoms. Compound 3 contains two triply bridging hydride ligands that were located and refined in the structural analysis. They bridge the Ru3 triangles on opposite sides of the cluster and exhibit the characteristic strongly shielded shift (6 -18.63 ppm) but show no discernible coupling to the platinum atoms. Due to the presence of the hydride ligands, all of the RuRu bond distances are unusually lon (Ru(l)-Ru(2) = 3.071(4) A, Ru(l)-Ru(3) = 3.006(4) , Ru(2)-Ru(3) =

1

(13)(a)Bour, J. J.; Kanters, R. P. J.; Schlebos, P. P. J.; Bos, W.; Bosman, W. P.; Behm, H.; Beurkers, P. T.; Steggerda, J. J. J. Organomet. Chem. 1987,329,405. (b) Briant, C. E.; Wardle, R. W. M.; Mingos, D. M. P. J.Organomet. Chem. 1984,267,C49. (c) Mingos, D. M. P.; Wardle, R. W. M. J. Chem. SOC.,Dalton Trans. 1986,73.

Cluster Synthesis

Organometallics, Vol. 14,No. 5, 1995 2237

Table 7. Intramolecular Bond Angles for 3a Pt(1)-Au( 1)-Ru( 1)

59.86(6) Pt(1)-Au( 1)-Ru(2) 60.70(7) Pt(1)-Au(l )-P( 1) 147.2(3) Ru( l)-Au(l)-Ru(2) 65.65(8) Ru(l)-Au(l)-P(l) 144.5(3) Ru(2)-Au(l)-P(l) 138.7(3) P ~ ( ~ ) - A u ( ~ ) - R u ( ~59.44(6) ) P ~ ( ~ ) - A u ( ~ ) - R u ( ~61.52(7) ) Pt(2)-Au(2)-P(2) 144.1(3) R u ( ~ ) - A u ( ~ ) - R u ( ~ )65.41(8) R u ( ~ ) - A u ( ~ ) - P ( ~ )143.0(3) Ru(5)-Au(2)-P(2) 143.0(3) Au( 1)-Pt( 1)-Pt(2) 118.03(6) Au(l)-Pt(l)-Pt(3) 118.55(5) Ad, l)-Pt( 1)-Ru( 1) 58.53(6) Au( l)-Pt( 1) - R u ( ~ ) 58.63(7) Au(l)-Pt(l)-Ru(B) 142.39(7) Au(l)-Pt(l)-Ru(6) 143.08(9) Pt(L)-Pt(l)-Pt(3) 60.35(5) Pt(2)-Pt( l)-Ru( 1) 92.36(7) Pt(Z)-Pt(l)-Ru(2) 59.47(7) Pt(S)-Pt(l)-Ru(B) 65.32(7) Pt(2)-Pt(l)-Ru(6) 94.68(8) Pt(3)-Pt(l)-Ru(l) 60.18(6) Pt(B)-Pt(l)-Ru(2) 91.40(6) Pt(S)-Pt(l)-Ru(5) 96.11(7) Pt(B)-Pt(l)-Ru(G) 61.74(7) Ru(l)-Pt(l)-Ru(P) 64.37(8) Ru(1)-Pt(1)-Ru(5) 154.28(8) Ru(l)-Pt(l)-Ru(G) 106.74(8) Ru(2)-Pt(l)-Ru(5) 110.0(1) Ru(2)-Pt(l)-Ru(6) 150.64(9) Ru(B)-Pt( 1)-Ru(6) 65.03(9) Au(Z)-Pt(2)-Pt(l) 117.32(6) Au(2)-Pt(2)-Pt(3) 120.39(6) A~(2)-Pt(2)-Ru(2) 141.84(7) Au(2)-Pt(2)-Ru(3) 143.80(8) Au(2)-Pt(2)-Ru(4) 59.50(7) Au(2)-Pt(2)-Ru(5) 58.10(7) Pt(l)-Pt(2)-Pt(3) 59.95(5) Pt(l)-Pt(2)-R~(2) 64.96(7) Pt(l)-Pt(2)-Ru(3) 94.96(8) Pt(l)-Pt(2)-Ru(4) 91.54(8) Pt(l)-Pt(B)-Ru(5) 59.26(7) Pt(3)-Pt(2)-Ru(2) 94.41(8) Pt(3)-Pt(2)-Ru(3) 60.80(7) Pt(3)-Pt(2)-Ru(4) 61.07(7) Pt(3)-Pt(2)-Ru(5) 92.23(7) R~(2)-Pt(2)-Ru(3) 65.18(7) 153.1(1) Ru(2)-Pt(2)-Ru(4) Ru(2)-Pt(2)-Ru(5) 109.55(9) R u ( ~ ) - P ~ ( ~ ) - R u ( 106.70(8) ~) Ru( 3)-Pt(2)-Ru(5) 150.8(1) Ru(4)-Pt(2)-Ru(5) 64.14(8) Pt(l)-Pt(3)-Pt(2) 59.716) Pt(l)-Pt(3)-Ru(l) 63.56(6) Pt(l)-Pt(3)-R~(3) 95.09(7) Pt(l)-Pt(3)-Ru(4) 92.31(6) Pt(l)-Pt(B)-Ru(G) 61.58(6) Pt(2)-Pt(3)-R~( 1) 94.01(7) Pt(2)-Pt(3)-Ru(3) 61.25(7)

Pt(2)-Pt(3)-Ru(4) 62.61(7) Pt(2)-Pt(3)-Ru(6) 94.21(7) Ru(l)-Pt(3)-Ru(3) 66.08(9) Ru( l)-Pt(3)-R~(4) 153.48(8) Ru(l)-Pt(3)-Ru(6) 109.1(1) R u ( ~ ) - P ~ ( ~ ) - R u ( 108.2(1) ~) Ru(3)-Pt(3)-Ru(6) 153.47(9) Ru(4)-Pt(3)-Ru(6) 63.7(1) 1) 61.62(6) Au( l)-Ru( 1)-R( Au(l)-Ru(l)-Pt(3) 117.72(9) Au(l)-Ru(l)-Ru(2) 57.63(7) Au(l)-Ru(l)-Ru(B) 116.2(1) Pt(l)-Ru(l)-Pt(B) 56.26(6) Pt(l)-Ru(l)-Ru(2) 58.61(7) Pt(l)-Ru(l)-Ru(B) 85.55(9) Pt(3)-Ru(l)-Ru(2) 85.9(1) Pt(3)-Ru( 1)-Ru( 3) 56.57(8) Ru(B)-Ru(l)-Ru(S) 58.58(9) Au(l)-Ru(2)-Pt(l) 60.67(7) Au( l)-Ru( 2)-Pt( 2) 116.2(1) Au(l)-Ru(2)-R~(l) 56.72(8) Au( l)-Ru( 2)-Ru( 3) 116.3(1) Pt(l)-R~(2)-Pt(2) 55.57(6) Pt(l)-Ru(2)-Ru(l) 57.02(7) Pt(l)-Ru(2)-Ru(3) 85.25(9) Pt(B)-Ru(2)-Ru(l) 85.68(8) Pt(2)-Ru(2)-Ru(3) 57.27(7) Ru( l)-Ru(2)-Ru( 3) 59.61(9) Pt(2)-Ru(3)-Pt(3) 57.95(6) Pt(2)-Ru(B)-Ru(l) 87.11(9) P ~ ( ~ ) - R u ( ~ ) - R u ( ~57.55(7) ) Pt(3)-Ru(3)-Ru(l) 57.35(8) P ~ ( ~ ) - R u ( ~ ) - R u ( ~88.3(1) ) R~(l)-Ru(3)-Ru(2) 61.81(9) Au(2)-Ru(4)-Pt(2) 61.06(7) A u ( ~ ) - R u ( ~ ) - P ~ ( ~117.2(1) ) A u ( ~ ) - R u ( ~ ) - R u ( ~ )56.94(8) A u ( ~ ) - R u ( ~ ) - R u ( ~116.5(1) ) Pt(2)-Ru(4)-Pt(3) 56.32(6) Pt(2)-Ru(4)-Ru(5) 59.17(7) Pt(2)-Ru(4)-Ru(6) 87.3(1) P ~ ( ~ ) - R u ( ~ ) - R u ( ~86.71(9) ) Pt(3)-Ru(4)-Ru(6) 58.09(8) R u ( ~ ) - R u ( ~ ) - R u ( ~ )59.5(1) Au(2)-Ru(B)-Pt(l) 115.8(1) Au(2)-Ru(5)-Pt(2) 60.37(7) A u ( ~ ) - R u ( ~ ) - R u ( ~ )57.65(8) Au(2)-Ru(5)-Ru(6) 116.1(1) Pt(l)-Ru(B)-Pt(a) 55.43(6) Pt(l)-Ru(S)-Ru(4) 84.87(8) Pt(l)-Ru(6)-Ru(6) 57.96(8) Pt(2)-Ru(5)-Ru(4) 56.68(7) Pt(2)-Ru(5)-Ru(6) 85.27(9) R u ( ~ ) - R u ( ~ ) - R u ( ~ )58.4( 1) Pt(l)-Ru( 6)-Pt(3) 56.68(6) Pt(l)-Ru(G)-Ru(4) 86.4(1) Pt(l)-Ru(G)-Ru(S) 57.01(8) Pt(3)-Ru(6)-Ru(4) 58.25(8) Pt(3)-Ru(6)-Ru(5) 88.3(1) R u ( ~ ) - R u ( ~ ) - R u ( ~ )62.0(1) M-C-0 (av) 173(4)

Angles are in degpees. Estimated standard deviati.ons in the least significant figure are given in parentheses.

2.973(3) A, R u ( ~ ) - R u ( ~=) 3.061(3) A, Ru(4)-Ru(6) = 2.953(4) A,and Ru(5)-Ru(6) = 2.986(4) A),but those Ru-Ru bonds that are bridged by the gold atoms (Ru(1)-Ru(2) and Ru(4)-Ru(5)) are the longest, which indicates that the gold atom also seems to produce a lengthening of the associated metal-metal bonds, as found in 2 above. It is notable that the gold-bridged Pt-Ru bonds are also longer than the others: Pt(1)Ru(1) = 2.857(3) A, Pt(l)-R~(2)= 2.908(3) A, Pt(2)Ru(4) = 2.843(3)A,and Pt(2)-Ru(5) = 2.921(3)A versus Pt(l)-R~(5)= 2.763(3) A,Pt(l)-Ru(6) = 2.793(3)A,Pt(2)-Ru(2) = 2.764(3) A, Pt(2)-Ru(3) = 2.756(3) A, Pt(3)-Ru(l) = 2.768(3) A, Pt(3)-Ru(3) = 2.774(3) A,

Pt(3)-Ru(4) = 2.802(3) A,and Pt(3)-Ru(6) = 2.797(3) A. The bonding similarities between H and Au(PR3) groupings have been investigated the0retical1y.l~Both are well-known to bond to one, two, or three transitionmetal atoms. However, Au(PR3) grouping appears to exhibit a preference for the ,us-bridging coordination when three or more additional transition-metal atoms are present in the mole~ule.~ It seems thus that this preference may have had a directing influence on the formation of the structure observed in 3. For example, compounds 1 and 2 each have one triple bridge (Hor Au(PR3)) and three edge-bridging hydride ligands. Compound 3,on the other hand, has four ,u3 groups. It is suspected that this result is directed, in a large part, by the tendency of the Au(PR3) groups to adopt the p3bonding modes. As expected, the Pts triangle in 3 lies midway between the two Ru3 triangles. Each ruthenium atom contains three linear terminal carbonyl ligands, each platinum atom has only one terminal carbonyl ligand, and the cluster contains the expected 124 valence electrons.12

Overall, the molecule has an approximate C2 symmetry with the CZaxis passing through the atom Pt(3) and the midpoint of the Pt(lI-Pt(2) bond. The molecule is thus chiral, and as a result the methylene groups on the PEt3 ligands are diastereotopic. Curiously, their inequivalence was not revealed in the lH NMR spectra, even when recorded a t -80 "C. Either the molecule is engaging in a rapid dynamic process that averages their environments or the chiral environment is simply too weak to reveal their inequivalence spectroscopically. We presume that compound 3 was formed by the addition of 2 equiv of [(PEt3)Aul+t o the corresponding dianion of 1 formed by removal of two protons. The reactions of metal carbonyl anions with [(PR3)Aulcontaining reagents is a well-established method for the preparation of gold-containing metal carbonyl cluster c0mp1exes.l~We have not yet been able t o isolate either the mono- or the dianion of 1 in a pure form as a salt, but these efforts are still in progress.

Acknowledgment. This research was supported by the National Science Foundation. Supplementary Material Available: Tables of positional parameters for t h e hydrogen atoms for 2 and anisotropic thermal parameters for 2 and 3 (5 pages). Ordering information is given on any current masthead page. OM9409940 (14)Evans, D. G.; Mingos, D. M. P. J. Organomet. Chem. 1982,232, 171. (15) (a)Hay, C. M.; Johnson, B. F. G.; Lewis, J.;McQueen, R. C. S.; Raithby, P. R.; Sorrell, R. M.; Taylor, M. J . Organometallics 1986,4, 202. (b) Johnson, B. F. G.; Kaner, D. A.; Lewis, J.; Raithby, P. R.; Sorrell, R. M.; Taylor, M. J. J . Chem. Soc., Chem. Commun. 1982,314. ( c ) Johnson, B. F. G.; Kaner, D. A.; Lewis, J.; Raithby, P. R.; Sorrell, R. M.; Taylor, M. J . Polyhedron 1982,I , 105.