Organometallics 1995, 14, 3486-3496
3486
Oxidative Addition of HSnR3 (R = Ph, n B ~to ) the Square-Planar Iridium(1) Compounds Ir(XR)(TFB)(PCy3) (XR = OMe, OEt, OiPr, OPh, SnPr)and Ir(C2Ph)L2(PCys) (L2 = TFB, 2CO) Miguel A. Esteruelas," Fernando J. Lahoz, Montserrat OlivBn, Enrique Oiiate, and Luis A. Oro Departamento de Quimica Znorganica, Znstituto de Ciencia de Materiales de Aragbn, Universidad de Zaragoza, CSZC, 50009 Zaragoza, Spain Received February 17, 1995@ The synthesis of the compounds Ir(OR)(TFB)(PCy3)(R = E t (2),'Pr (3),Ph (4);TFB = tetrafluorobenzobarrelene), 1r2(CO)dPCy3)~(5),Ir(S"Pr)(TFB)(PCyd (6), [Ir(p-S"Pr)(CO)(PCy3)]2 (7), Ir(CzR)(TFB)(PCyd(R = Ph (9),Cy (lo),COzMe (ll),SiMe3 (12)),and Ir(CzPh)(CO)z(PCy3)(13)is described. The complexes 2-4 and 6 react with HSnR3 in a 1:2 molar ratio to give I ~ H z ( S ~ R ' ~ ) ( T F B ) ((PRC= ~ ~Ph ) (14),"Bu (15))and RXSnR3 (X = 0, S). The structure of 14 was determined by an X-ray investigation. Compound 14 crystallizes in the space group Pi (No. 2) with a = 10.923(1)A,b = 10.943(1)A, c = 19.6790) A,a = 75.076(5)", ,8 = 77.504(5)", y = 72.606(5)", and 2 = 2. The coordination geometry around the iridium atom could be rationalized as being derived from a highly distorted octahedron with the triphenylstannyl group and the tricyclohexylphosphine ligand occupying pseudo-trans positions (Sn-Ir-P = 129.46(3)"). In solution 14 and 15 are fluxional. The fluxional process, with values for @ of 13.4 f 0.9 (14)and 12.7 f 0.7 (15)kcaymol and for AS*of 3.0 f 3.0 (14)and -1.6 f 2.0 (15)eu, involves the relative positions of the diolefin atoms. The alkynyl derivative 9 reacts with HSnR3 to afford IrH(CzPh)(SnR3)(TFB)(PCyd( R = Ph (19),"Bu (20)).Under carbon monoxide atmosphere, 19 leads to 1rH(C~Ph)(SnPhd(C0)dPCys) (21) and tetrafluorobenzobarrelene. Compound 21,and the related derivative IrH(CzPh)(SnnBu3)(CO)z(PCy3)(22)can be also obtained by oxidative addition of the corresponding stannanes to 13. The complexes 14,19,and 21 catalyze the addition of HSnPh3 to phenylacetylene, and from all experiments cis-PhCH=CH(SnPh3) and trans-PhCH=CH(SnPhs) were obtained.
Introduction Vinylsilanes and vinylstannanes have been shown to be versatile intermediates in organic synthesis.l Vinylsilanes are usually prepared by catalytic addition of silanes to alkynes. From a mechanistic point of view, the hydrosilylation reactions involve conventional oxidative addition, insertion, and reductive elimination steps.2 In this respect, the investigation of the oxidative addition of silanes to unsaturated transition metal complexes is of great interest and has received increasing attention in recent years.3 @Abstractpublished in Advance ACS Abstracts, J u n e 15, 1995. (1)(a) Chan, T. H. Acc. Chem. Res. 1977,10, 442.(b) Hurdlike, P. F. in New Applications of Organometallic Reagents in Organic Synthesis; Seyferth, D., Ed.; Elsevier: Amsterdam, The Netherlands, 1976. ( c )Cook, F.; Moerk, R.; Schwindeman, J.; Magnus, P. J . Org. Chem. 1980,45,1406.(d) Negishi, E.Organometallics in Organic Synthesis, John Wiley and Sons: New York, 1980.(e) Neumann, W.P. Synthesis 1987,665.(DFleming, I.; Dunogues, J.; Smithers, R. H. Org. React. 1989,37,57. (g) Kumar Das, V. G.; Chu C.-K. I n The Chemistry ofthe Metal-Carbon Bond; Hartley, F. R., Patai, S., Eds.; Wiley: New York, 1985;Vol. 3. (2) Chalk, A. J . ; Harrod, J. F. J . Am. Chem. SOC.1966,87,16.(b) Schroeder, M.; Wrighton, M. S. J . Orgunomet. Chem. 1977,128,345. (c) Dickers, H. M.; Haszeldine, R. N.; Mather, A. P.; Parish, R. V. J . Organomet. Chem. 1978,161,91. (d) Randolph, C. L.; Wrighton, M. S. J . A m . Chem. SOC.1986,108, 3366. (e) Seitz, F.; Wrighton, M. S. Angew. Chem., Int. Ed. Engl. 1988,27, 289.(D Ojima, I.; Clos, N.; Donovan, R. J.; Ingallina, P. Organometallics 1990, 9, 3127. (g) Esteruelas, M. A.; Oro, L. A.; Valero, C. Organometallics 1991,10,462. ( h ) Duckett, S. B.; Perutz, R. N. Organometallics 1992, 12, 90. (i) Esteruelas, M. A.; Herrero, J.; Oro, L. A. Organometallics 1993,12, 2377.
The stereoselective formation of vinylstannanes by addition of alkyl- or arylstannanes to alkynes requires the presence of a transition metal ~ a t a l y s t .Although, ~ at first glance, there should not be a great difference between the catalytic hydrosilylation and hydrostannation of alkynes, the applicability of catalyst precursors related to those used in hydrosilylation has been scarcely investigated in hydrostannation reactions. If these catalyst precursors were active as hydrostannation catalysts, one would expect mechanistic similarities. However, the oxidative addition af alkyl- or arylstannanes to unsaturated transition metal complexes has received less attention than the oxidative addition of silane^.^ In addition, it should be noted that the comparison of physical and chemical properties for ( 3 ) (a)Tilley, T. D. In The Chemistry oforganic Silicon Compounds;
Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1989.(b) Schubert, U.Transition Met. Chem. 1991,16, 136.
(4)(a)Stille, J. K. Angew. Chem., Int. Ed. Engl. 1986,25,508.(b) Mitchell, T. N.; Amamria, A,; Killing, H.; Rutschow, D. J. Organomet. Chem. 1986,304, 257. (c) Kikukawa, K.; Umekawa, H.; Wada, F.; Matsuda, T. Chem. Lett. 1988, 881. (d) Zhang, H.X.; Guibe, F.; Balavoine, G . J . Org. Chem. 1990, 55, 1857. (e) Mitchell, T. N.; Schneider, U. J. Organomet. Chem. 1991,405,195. (5)(a) Lappert, M. F.; Travers, N. F. J . Chem. SOC.,Chem. Commun. 1968,1569.(b) Luo, X.-L.; Schulte, G. K.; Demou, P.; Crabtree, R. H. Inorg. Chem. 1990,29,4268.(c) Cabeza, J. A.; Llamazares, A.; Riera, V.; Triki, S.; Ouahab, L. Organometallics 1992,11,3334. (d)Schubert, U.;Gilbert, S.; Mock, 9. Chem. Ber. 1992,125,835. (e) Seebald, S.; Mayer, B.; Schubert, U. J . Organomet. Chem. 1993,462,225. (DClark, G.R.; Flower, K. R.; Rickard, C. E. F.; Roper, W. R.; Salter, D. M.; Wright, L. J. J . Organomet. Chem. 1993,462,331.
0276-7333/95/2314-3486$09.00/00 1995 American Chemical Society
Square-Planar Iridium(I) Compounds
Organometallics, Vol. 14, No. 7, 1995 3487 Scheme 1
7b
F R = Ph (9), Cy (lo), C02Me (ll), SiMe3 (12)
analogous series of hydridosilyl and hydridostannyl complexes may be used in developing a better understanding of bonding interactions in these systems. We have previously reported that the treatment of IrClsxHzO with tetrafluorobenzobarrelene (TFB) in refluxing methanoywater leads to IrCl(TFB12in nearly quantitative yield.6 The accessibility of this compound has promoted the development of an extensive chemistry of neutral and cationic complexes, including Ir(vlOC(O)CH3)(TFB)(PR3)(PR3 = PPh3, PCy3, P'Pr3) and Ir(v1-OC(0)CH3)(C0)2(PCy3), which show significant differences with respect t o the chemistry of the typical iridium-1,5-cyclooctadiene m ~ i e t y . Recently, ~,~ we have also observed that the oxidative addition of HSiR3 t o I ~ ( ~ ~ ~ - O C ( O ) C H ~ ) (Lz L Z= ( PTFB, C ~ ~ 2CO) ) affords the dihydridosilyl derivatives IrH2(SiR3)Lz(PCy3) (L2 = TFB? 2C09), which have been found to promote silicon-carbon bond formation in hydrosilylation and dehydrogenative silylation of phenylacetylene.s As a continuation of our work in this field, we have now investigated the oxidative addition of HSnPhs and HSn"Bu3 to the new square-planar complexes Ir(XR)(TFBXPCy3) (XR = OMe, OEt, O'Pr, OPh, SnPr) and Ir(CzPh)Lz(PCys)(L2 = TFB, 2CO). In this paper, we describe the results obtained from this study, as well (6)Uson, R.; Oro, L. A.; Carmona, D.; Esteruelas, M. A,; Foces-Foces, C.; Cano, F. H.; Garcia-Blanco, S.J. Organomet. Chem. 1983,254,249. ( 7 ) ( a ) Uson, R.; Oro, L. A.; Carmona, D.; Esteruelas, M. A. J. Organomet. Chem. 1984,263,109.(b) Uson, R.;Oro, L. A.; Carmona, D.; Esteruelas, M. A,; Foces-Foces, C.; Cano, F. H.; Garcia-Blanco, S.; Vazquez de Miguel, A. J. Organomet. Chem. 1984,273,111. (c) Oro, L. A,; Carmona, D.; Esteruelas, M. A.; Foces-Foces, C.; Cano, F. H. J. Organomet. Chem. 1986,307,83. (d) Ferndndez, M.J.; Esteruelas, M. A.; Covarrubias, M.; Oro, L. A. J. Organomet. Chem. 1986,316, 343.(e) Esteruelas, M. A.; Oro, L. A,; Apreda, M. C.; Foces-Foces, C.; Cano, F. H.; Claramunt, R. M.; L6pez, C.; Elguero, J.; Begtrup, M. J. Organomet. Chem. 1988, 344, 93. (D Garcia, M. P.; Lopez, A. M.; Esteruelas, M. A.; Lahoz, F. J.; Oro, L. A. J. Chem. Soc., Dalton Trans. 1990, 3465.(g) Garcia, M. P.; L6pez. A. M.; Esteruelas, M. A.; Lahoz, F. J.; Oro, L. A. J . Organomet. Chem. 1990,388, 365.(h) Esteruelas, M. A.; Garcia, M. P.; Lopez, A. M.; Oro, L. A. Organometallics 1991, 10,127. (8) Esteruelas, M. A.; Niirnberg, 0.;Olivan, M.; Oro, L. A.; Werner, H. Organometallics 1993,12,3264. (9)Esteruelas, M. A.; Lahoz, F. J.; Olivan, M.; OAate, E.; Oro, L. A. Organometallics 1994,13,4246.
13
as the catalytic activity of some of the prepared compounds in the hydrostannation of phenylacetylene with HSnPhs.
Results and Discussion Synthesis and Characterization of Ir(XR)("FB)(PCys) (XR = OEt, O'Pr, OPh, SnPr),Ir(C2R)(TFB)(PCys) (R = Ph, Cy, C o m e , SiMed, and Ir(C2Ph)(C0)2(PCys). These compounds were prepared according to the reactions shown in Scheme 1. Treatment of Ir(OMe)(TFB)(PCy3)(1) with ethanol, 2-propanol, and phenol leads to the terminal alkoxide compounds 2-4, which were isolated as orange solids in 58%-71% yield. The most noticeable absorption in the IR spectra in Nujol are very strong bands between 1255 and 1055 cm-l, assigned to the v(C-0) vibration of the alkoxide groups. The 'H NMR spectra in benzene-& are compatible with the square-planar structures shown in Scheme 1. The characteristic resonances of the tetrafluorobenzobarrelene diene are two broad signals a t about 5.2 and 3.5 ppm. The first signal is attributable to the tertiary CH protons and the second signal to the olefinic protons trans to the tricyclohexylphosphine ligand. The resonances due to the olefinic protons trans to the alkoxide group are masked by the aliphatic resonances (2.00-1.10 ppm) of the tricyclohexylphosphine ligand. The 31P(1H}NMR spectra show singlets at 19.0 (21, 18.8 (31, and 19.6 (4) ppm. The preparation of several iridium(1) alkoxide compounds of the type tran~-Ir(OR)(CO)(PPh3)2 has been previously reported. They were obtained by metathesis of chlorides.1° Under carbon monoxide atmosphere, the complexes 2 and 3 evolve t o the hexacarbonyl derivative S, which was isolated as a yellow solid in 40% yield. In agreement with the IR spectra previously reported for related (10)(a) Rees, W. M.; Churchill, M. R.; Fettinger, J. C.; Atwood, J. S. Organometallics 1985,4 , 2179. (b) Rees, W. M.; Atwood, J. D. Organometallics 1985,4 , 402. (c) Churchill, M. R.; Fettinger, J. C.; Rees, W. M.; Atwood, J. D. J. Organomet. Chem. 1986,308,361.(d) Bryndza, H.E.; Tam, W. Chem. Rev. 1988,88,1163.
3488 Organometallics, Vol. 14, No. 7, 1995 Mz(C0)6(PR3)2 (M = Co, Rh, Ir) complexes," the IR spectrum of 5 in dichloromethane shows a very strong v(C0) absorption a t 1945 cm-'. The 31P{1H} NMR spectrum in benzene-de contains a singlet at 21.1 ppm. While this work was in progress, Atwood et al. reported that the carbonylation of trans-Ir(CO)(OR){P(p-tolyl)s}z (R = H, Me, C6HsMe) yields Ir~(CO)s{P(p-tolyl)3}z.~~ The reaction of 1 with propanethiol in acetone affords the thiopropoxide compound 6 as an orange solid. The presence of the thiolato ligand in this complex is supported by the lH NMR spectrum, which shows a triplet at 2.59 ppm (JH-H= 7.1 Hz), assigned to the protons of the -CHzS group. The 31P{1H}NMR spectrum shows a singlet at 16.7 ppm. When a slow stream of carbon monoxide is passed through a dichloromethane solution of 6, the dicarbonyl compound 7 is formed. Complex 7 was isolated as an orange solid in 78% yield. According to the lH and 3lP{ lH} NMR spectra, it is a mixture of the isomers 7a and 7b in a 7:3 molar ratio. In the 'H NMR spectrum the isomer 7a, with inequivalent thiolato groups, gives rise to two -CH2S signals at 3.80 and 2.99 ppm. The first signal, assigned to the thiolato group trans to the phosphine ligands, appears as a multiplet due to coupling with the phosphine ligands and the protons of the -CHz-CHzS group. The second signal, assigned t o the thiolato group trans to the carbonyl ligands, appears as a triplet with a H-H coupling constant of 7.5 Hz. The -CHzS protons of the isomer 7b, with magnetically inequivalent thiolato groups, appear at 3.25 ppm as the A&z part of a second order AzA'2BzB'zXX' splitting pattern. The 31P{'H} NMR spectrum of 7 contains two singlets at 29.1 (7a) and 30.9 (7b)ppm. The bent configurations shown in Scheme 1 are proposed on the basis of the above mentioned spectroscopic data and are in agreement with X-ray diffraction studies previously carried out on related compounds.13 The reaction of formation of 7, which can be easily monitored by IR spectroscopy in dichloromethane solutions, proceeds via the cis-dicarbonyl intermediate Ir(SnPr)(CO)z(PCy3)(81, which by loss of a carbon monoxide molecule affords 7. In the IR spectrum, the intermediate 8 gives rise to two v(C0) absorptions at 2035 and 1960 cm-l. Treatment of 1 with the stoichiometric amount of phenylacetylene, cyclohexylacetylene,methylpropiolate, and trimethylsilylacetylene, in acetone, yields the alkynyl compounds 9-12, which were isolated as red or brown-red solids in 40%-70% yield. The presence of an alkynyl ligand in these compounds is mainly supported by the IR and l3C{lH) NMR spectra. The IR spectra in Nujol contain a v(C=C) absorption between 2020 and 2080 cm-l. While the l3C{lH) NMR spectra show doublets between 110 and 144 ppm with P-C (11)(a)Ibers, J. A. J. Organomet. Chem. 1968,14,423. (b) Whyman, R. J. Chem. Soc., Dalton Trans. 1972, 1375. ( c ) Malatesta, L.; Angoletta, M.; Caglio, G. J. Organomet. Chem. 1974,73,265. (12)Randall, S.L.;Miller, C. A,; See, R. F.; Churchill, M. R.; Janik, T. S.; Lake, C. H.; Atwood, J. D. Organometallics 1994,13, 5088. (13)(a) Bonnet, J. J.; Kalck, P.; Poilblanc, R. Inorg. Chem. 1977, 16, 1514. (b) Cruz-Garritz, D.;Rodriguez, B.; Torrens, H.; Leal, J. Transition Met. Chem. 1984,9,284. ( c ) Claver, C.; Masdeu, A. M.; Ruiz, N.; Foces-Foces, C.; Cano, F. H.; Apreda, M. C.; Oro, L. A.; GarciaAlejandre, J.; Torrens, H. J. Organomet. Chem. 1990, 398, 177.(d) Polo, A,; Claver, C.; Castillon, S.;Ruiz, A.; Bayon, J. C.; Real, J.; Mealli, C.; Masi, D. Organometallics 1992,II,3525.(e) Masdeu, A. M.; Ruiz, A.; Castillon, S.; Claver, C.; Hitchcock, P. B.; Chaloner, P. A.; Bo, C.; Poblet, J. M.; Sarasa, P. J. Chem. Soc., Dalton Trans. 1993,2689.
Esteruelas et al.
coupling constants of about 12 Hz, which were assigned to the a-carbon atom of the alkynyl groups. The /3-carbon atoms appear as singlets between 118 and 134 ppm. In agreement with the structure shown in Scheme 1,the 13C{lH)N M R spectra also contain two resonances due to the olefinic carbon atoms of the tetrafluorobenzobarrelene ligand at about 62 and 45 ppm. The resonances at lower field were assigned t o the carbon atoms disposed trans to the phosphine ligand, and appear as doublets with P-C coupling constants of about 12 Hz. While the resonances at higher field were assigned t o the carbon atoms disposed trans to the alkynyl ligands, and appear as singlets. In the lH NMR spectra, the diolefin ligand gives rise to three broad resonances at about 5.25 (CH), 4.00 (CH= trans to PCy3), and 2.50 (CH= trans to CECR) ppm. The 31P{lH} NMR spectra show singlets between 22 and 24 PPm. The tetrafluorobenzobarrelene diolefin of 9 can be displaced by carbon monoxide. Thus, the passage of a slow stream of this gas through a dichloromethane solution of 9, affords the cis-dicarbonylcomplex 13. This compound was isolated as a yellow solid in 66% yield. In accordance with the mutually cis disposition of both carbonyl ligands, the IR spectrum in Nujol shows two v(C0) bands at 2045 and 1970 cm-l. In addition, it should also be mentioned the absorption at 2100 cm-l, assigned to the v(C=C) vibration of the terminal alkynyl ligand. The 31P{1H} NMR spectrum in benzene-d6 contains a singlet at 27.6 ppm. Reactions of Ir(OR)(TFB)(PCy3)(R = Me, Et, 'Pr, Ph) and Ir(SnPr)(TFB)(PCy3)with H S n P h and HSnnBus. The complexes 1-4 react with HSnPhs and HSn"Bu3 in a 1:2 molar ratio in toluene to give the dihydrido(stannyl)iridium(III) derivatives 14 and 15 (Scheme 21, which were isolated as white air-stable powders in high yields (60%-90%). These reactions also lead to the formation of the corresponding ROSnR3, characterized for R = Me, 'Pr, and Ph and for R = Ph by mass spectroscopy. Similarly, the treatment of 6 with HSnPh3 in a 1:2 molar ratio in toluene yields 14 and "PrSSnPhs. The formation of 14 and 15 from the reactions of 1-4 or 6 with HSnPh3 and HSn"Bu3, respectively, most probably involves the oxidative addition of the stannane t o the starting material to give Ir(XR)H(SnR3)(TFBI(PCy3)(16). Thus, the subsequent elimination of RXSnR3 followed by the oxidative addition of a second stannane molecule to the intermediate IrH(TFB)(PCy3) (17) should afford 14 and 15 (Scheme 2). We have tried t o detect the intermediates 16 and 17 by addition of 1 equiv of HSnPh3 to an NMR tube containing a solution of 1 in benzene-de. However, under these conditions, only a mixture of the starting material, 14, and MeOSnPh3 was observed. Compounds 14 and 15 were identified by elemental analysis and IR and 'H and 31P{1H} NMR spectroscopies. Complex 14 was, furthermore, characterized by an X-ray crystallographic study. An ORTEP drawing of the molecular structure of 14 is presented in Figure 1. Selected bond distances and angles are listed in Table 1. The coordination geometry around the iridium atom could be rationalized as derived from a highly distorted octahedron with the triphenylstannyl and the tricyclo-
Organometallics, Vol. 14, No. 7,1995 3489
Square-Planar IridiumW Compounds Scheme 2
1-4, 6
Ci46
+ZR
F
Fi31
C
16
- RXSnR'3 F
Figure 1. Molecular diagram of complex 14. Thermal ellipsoids are shown at the 50% level.
'
-
PCY3
F 17
HSnR'3
SnRo3
F
x=o,s
PCY3
R' = Ph (14), "Bu (15)
Table 1. Selected Bond Lengths (A) and Angles (deg) for the Complex IrHs(SnPb)(TFB)(PCys)
(14)" Ir-Sn Ir-P Ir-C(8) Ir-C(9) Ir-C(11) Sn-Ir-P Sn-Ir-M(l) Sn-Ir-M(2) Sn-Ir-H(l) Sn-Ir-H(2) P-Ir-MU) P-Ir-M(2) P-Ir-H( 1) P-Ir-H(2) M(l)-Ir-M(2) M(1)-Ir-H(l)
2.6122(5) 2.363(1) 2.235(6) 2.241(6) 2.210(4) 129.46(3) 107.5(1) 105.9(1) 68(2) 64(2) 110.1(1) 119.3(1) 86(2) 77(2) 66.9(2) 160(2)
Ir-C(12) Ir-H(l) Ir-H(2) C(8)-C(9) C(ll)-C(12) M(l)-Ir-H(2) M(2)-1r-H(1) M(2)-Ir-H(2) H(l)-Ir-H(2) C(8)-C(7)-C(12) C(7)-C(8)-C(9) C(8)-C(9)-C( 10) C(9)-C( lO)-C( 11) C(lO)-C(ll)-C(l2) C(ll)-C(l2)-C(7)
2.231(4) 1.48(5) 1.55(5) 1.397(6) 1.409(6) 99(2) 95(2) 161(2) 96(3) 99.5(4) 112.4(4) 113.3(4) 98.3(4) 113.3(4) 112.0(4)
M(1) and M(2) represent the midpoints of the C(8)-C(9) and C(ll)-C(12) olefinic double bonds, respectively. Q
hexylphosphine ligands occupying pseudo-trans positions (Sn-Ir-P = 129.46(3)"),at opposite sides of an ideal coordination plane defined by the two cis-hydrido ligands (H(l)-Ir-H(2) = 96(3)") and the chelate diolefinic molecule. The small Sn-Ir-P angle is notable, and may be due to the different steric requirements, relatively small for the hydridos and comparatively large for the diene molecule and PCy3 and SnPhs ligands. Angular distorsions in hydrido complexes are not unusual. We note
that in the complex IrH2(SiEt3)(COD)(AsPh3)(COD = 1,5-~yclooctadiene)the angle between the triethylsilyl and the triphenylarsine ligands is 133.4O(4Y'.l4 A similar observation has been reported for the complex IrHz(SnCls)(PPh&,,in which the major deviation from the ideal octahedral geometry arises from the P-Ir-P angle (145.95(9)")involving two chemically equivalent phosphine groups, which are pseudo-trans to one Values about 150" have been also reported for the related angle in the complexes mer-IrH3(PPh3)3,16[(PPb)A u @ - H ) I ~ H ~ ( P P ~ ~mer-[IrH2(CO)(PPh3)3I+,l8 )~I+,'~ and [IrH2(PPhsh ( C ~ H E S ) ~ I + . ~ ~ The Ir-Sn distance (2.6122(5) A) is significantly shorter than the value of 2.75 A suggested for an iridium-tin single bond and, thus, indicates the presence of some partial multiple bond character.20 The Ir-P, Ir-C, and Ir-H distances are clearly in the expected range and deserve no further comment. In agreement with the structure shown in Figure 1, the IR spectra of 14 and 15 in Nujol contain one (15)or two (14)absorptions at about 2100 cm-', attributable to v(1r-H). In the lH NMR spectra in toluene-& the hydrido resonances appear as a doublet a t -15.37 (14) and -15.98 (15)with P-H coupling constants of 20.1 and 21.3 Hz, respectively. The 31P{1H}NMR spectra show singlets a t 14.8 (14)and 13.1 US),along with the satellites due to l17Snand l19Snisotopes. In accordance with the pseudo-trans positions of the stannyl and phosphine ligands, the values of the P-ll9Sn coupling constants are 737.0 (14)and 528.4 (15)Hz, while the values of P-l17Sn coupling constants are 641.8 (14)and 504.1 (15)Hz. Under off-resonance conditions, both singlets are split into triplets due to the P-H coupling. (14)Ferndndez, M. J.;Esteruelas, M.-A,;ON,L. A,; Apreda, M. C.; Foces-Foces, C.; Cano, F. H. Organometallics 1987, 6, 1751. (15)Kretschmer, M.; Pregosin, P. S.; Albinati, A.; Togni, A. J. Organomet. Chem. 1985,281, 365. (16)Clark, G.R.;Skelton, B. W.; Waters, T. N. Znog. Chim. Acta 1976, 12, 235. (17)Lehner, H.; Matt, D.; Pregosin, P. S.; Venanzi, L. M.; Albinati, A. J.Am. Chem. SOC.1982, 104, 6825. (18)Bird, P.; Harrod, J. F.; Than, K. A. J. Am. Chem. Soc. 1974, 96, 1222. (19)Shchez-Delgado, R. A.; Herrera, V.; Bianchini, C.; Masi, D.; Mealli, C. Znog. Chem. 1993,32, 3766. (20) Churchill, M. R.; Lin, K.-K. G. J.Am. Chem. SOC.1974,96, 76.
3490 Organometallics, Vol.14, No. 7,1995
Esteruelas et al.
Table 2. Activation Parameters for Complexes 14, 15, and 18 complex T,,K AGb, kcal/mola m,kcal/molb AS*, eub 14 15 18
273 f 1 293 f 1 263 f 1
12.8 f 0.1 13.6 f 0.1 13.0 i~0.1
13.4 f 0.9 12.7 f 0.7 16.5 j, 0.7
3.0 f 3.0 -1.6 f 2.0 13.6 f 2.6
343K
a Calculated from T,and Avo with the equations k, = (n/J2)Avo and AGb/RT, = ln(&R/nNh) + ln(TJAvo). Errors shown are propagated from the estimated errors in T,.* Calculated from the slopes and intercepts of the Eyring plots. Error ranges listed correspond to one standard deviation.
The disposition of ligands as shown in Figure 1leads to a situation in which the aliphatic CH protons of the tetrafluorobenzobarrelene diolefin are chemically in-
333 K
i ' L K 323
equivalent; furthermore, the protons of each carboncarbon double bond are also mutually inequivalent, although both olefin bonds are chemically equivalent. As would be expected for this arrangement, the 'H NMR spectra of 14 and 16 display two aliphatic and two olefinic signals at -60 "C. However, at room temperature, the spectra only contain an aliphatic and an olefinic resonance. This behavior suggests that the complexes 14 and 16 have a rigid structure only a t low temperature. At room temperature an intramolecular exchange process takes place which involves the relative positions of the diolefin atoms (eq 1h21 F
F)qJ$r-" F
F
f
SnR3
I -H PCY3
=
Wi':; F
313 K 293 K 273 K 263 K
253 K
SnR3
'
243 K (1)
PCY3
A similar fluxional process has been previously observed for the dihydridosilyl complex IrHz(SiPhs)(TFB)(PCy3) (18).8 We suggest that the intramolecular exchange process involving the relative positions of diene atoms could proceed via the five-coordinateintermediate IrHz(SiPhs)(TFB),which should be formed by dissociation of the phosphine ligand. In accordance with this, we observed that the addition of P'Pr3 to a benzene46 solution of 18 in a 1:l molar ratio leads t o a mixture of the starting material, IrH2(SiPh3)(TFB)(PiPr3),PCy3, and P'Pr3 in a 1:l:l:l molar ratio after 22 h. Under the same conditions, the addition of PiPr3 to benzene46 solutions of 14 and 15 does not affect the spectra of these compounds. This indicates that, during the fluxional process of 14 and 16, the dissociation of the phosphine does not take place. The free energies of activation for the intramolecular exchange of the diolefin at coalescence (AG?) for 14,16, and 18 were calculated using the temperature of coalescence (T,)of the olefinic resonances and the chemical shift difference of these resonances projected from the slow-exchange limit (Av,). The resulting values, listed in Table 2, show that the free energy barriers for the three compounds are similar. In order to obtain additional information, we have utilized lineshape analysis as an alternative procedure. As an example, the observed resonances for 15 as a function of the temperature are shown in Figure 2. Linear leastsquares analysis of the Eyring plots for the kinetic data provides values of A P and AS* (Table 2) for the three compounds. (21)The 31P{1H} NMR spectra and the signal of the hydrido ligands are temperature invariant,
233 K
223 K 1
I
I
4.0
3.5
3.0
I
2.5 ppm
Figure 2. Variable-temperaturelH NMR study (in toluene&) at 299.949 MHz of the olefinic protons of the tetrafluorobenzobarrelene ligand of 15. For the silyl complex 18 the significative positive value for the entropy of activation (13.6 f 2.6 eu) is in agreement with the dissociation of the phosphine ligand during the fluxional process while, for 14 and 16, the values for the entropy of activation, close to zero, are in agreement with the fact that the dissociation of phosphine does not take place. If the dissociation of phosphine from 14 and 16 does not occur during the intramolecular exchange of the diolefin atoms, it could be proposed that for the stannyl compounds the fluxional process involves the dissociation of one arm of the chelating tetrafluorobenzobarrelene diolefin, followed by rotation of the diene around the other iridium-olefin bond. This implies that the iridium-tetrafluorobenzobarrelene bond is more labile for 14 and 16 than for 18. In favor of this, we have found that the reaction of 14 with carbon monoxide produces the displacement of the diene and the formation of Ir(SnPh3)(C0)3(PCy3),while under the same and conditions 18 affords Ir(171:r2-C12F4H7)(C0)2(PCy3) H S i p h ~ . The ~ complex Ir(SiPh3)(C0)3(PCy3)is also known and can be easily prepared by reaction of Irf+ OC(O)CH3)(C0)2(PCy3)with HSiPh3.9 For late transition metal-silicon and metal-tin bonds, some multiple bond character has been
Square-Planar Iridium(I) Compounds
Organometallics, Vol. 14, No. 7, 1995 3491
s~ggested.~ This " ~multiple-bond ~~~~~ character has been generally attributed to d,-d, bonding involving donation of d-electron density from the transition metal to empty silicon or tin orbitals of appropiate symmetry. Because the energy difference between the iridium and tin d-orbitals (5d-5d) is smaller than that between the iridium and silicon d-orbitals (5d-3d), one should expect a better iridium-tin overlap and, therefore, a stronger iridium-tin bond. The behavior of 14 and 18 toward carbon monoxide is in agreement with this. The higher contribution of the d,-d, interaction to the iridium-tin bond compared to the iridium-silicon bond could also explain the different behavior of these compounds in solution. Thus, the transfer of electron density from the iridium to the stannyl groups should increase the electron-donor capacity of the phosphine hindering its dissociation, while the capacity of the iridium to back bond to the diolefin should decrease, favoring the dissociation of one arm of the tetrafluorobenzobarrelene ligand. The lability of one arm of the diene in 14 and 15 may also be a result of the steric demands of the tin atom compared to the silicon one. Reactions of Ir(CnPh)(TFB)(PCys)and Ir(C2Ph)(C0)2(PCys) with H S n P h and HSnnBw. The alkynyl-diolefin complex 9 also reacts with HSnPh3 and HSn"Bu3. Thus, the treatment of a toluene solution of this complex with HSnPh3 or HSn"Bu3 leads immediately to the formation of a light yellow solution from which the complexes 19 or 20 can be isolated as white solids (eq 2). c
-
PCY3
+
HSnR,
-
F
Hz. The 31P{lH} NMR spectrum contains a singlet at -1.9 ppm, together with the satellites due to the ll7Sn and l19Sn isotopes. In accordance with the trans position of the stannyl and phosphine ligands, the values of P-l17Sn and P-llgSn coupling constants are 715.9 and 735.6 Hz, respectively. Under off-resonance conditions the singlet is split into a doublet due to P-H coupling. Complex 20 was isolated in 74% yield. In the IR spectrum in Nujol, the v(1r-H) and v(C=C) absorptions appear a t 2085 and 2020 cm-l. The 'H NMR spectrum shows the expected resonances of the phosphine and stannyl ligands along with six resonances due t o the diene at 5.31 and 5.08 (CH) and at 3.54,3.31,3.21,and 2.30 (CH=) ppm, and a doublet at -13.68 ppm with a P-H coupling constant of 26.1, which was assigned t o the hydrido ligand. In the 13C{'H} NMR spectrum, the diolefinic carbon atoms of the diene give rise to four signals at 37.80,37.40,36.57,and 35.85 ppm, while the Cp and C, carbon atoms of the alkynyl group appear at 107.29 and 76.95 ppm as doublets with P-C coupling constants of 3.7 and 18.4 Hz, respectively. The 31P{1H} NMR spectrum contains a singlet at -2.0 ppm along with the corresponding tin satellites ( J p - 1 1 9 ~= ~ 550.5 Hz, Jp-117~" = 525.9 Hz). Under off-resonance conditions, this singlet is split into a doublet due to the P-H coupling. The tetrafluorobenzobarrelene diolefin of 19 is also labile. Thus, under carbon monoxide atmosphere, this compound yields the dicarbonyl derivative 21 and tetrafluorobenzobarrelene (eq 3), according with the above mentioned dissociation of one arm of the chelating diolefin. c/Ph
9
+2co
F
-
PCY3
+
R = Ph (19),"Bu (20)
Complex 19 was isolated in 83%yield, and characterized by elemental analysis, IR, and lH, 31P{1H}, and 13C{lH} NMR spectroscopy. The most noticeable absorptions in the IR spectrum in Nujol are two bands at 2113 and 2058 cm-', which were assigned to the vibrations v(1r-H) and v(CW), respectively. In the lH NMR spectrum, in benzene-de a t room temperature, the hydrido ligand gives rise t o a broad resonance at -13.32 ppm. In toluene-de at -60 "C, this signal is a broad doublet with a P-H coupling constant of 21.6 Hz. In agreement with the structure proposed for 19 in eq 2, lH NMR spectra a t room temperature and at -60 "C show six resonances €or the protons of the diene at 5.21 and 4.98 (CHI and at 3.72, 3.47, 3.42, and 2.07 (CH-1 ppm. In the 13C{'H} N M R spectrum, the olefinic carbon atoms of the tetrafluorobenzobarrelene ligand display four signals a t 43.90,39.80,36.25,and 36.10 ppm, while the Cp and C, carbon atoms of the alkynyl group appear at 109.01 and 72.30 ppm, respectively. The second signal as a doublet with a P-C coupling constant of 17.5 (22) Ho,Y.K.; Zuckerman, J. J.J . Organomet. Chem. 1973,49, 1.
TFB
(3)
PCY3 21
Complex 21 was isolated as a white solid in 75%yield. In agreement with the mutually cis disposition of the two carbonyl ligands, the IR spectrum of 21 in Nujol has two v(C0) absorptions at 2040 and 2000 cm-l. The 'H NMR spectrum in benzene& shows a t -9.42 ppm a doublet with a P-H coupling constant of 14.8 Hz. The satellites due to the tin isotopes are also observed near of this resonance. The value of the Sn-H coupling constant, 30 Hz, strongly supports the cis disposition of the triphenylstannyl group and the hydrido ligand. In the 13C(lH} NMR spectrum the Cp and C, carbon atoms of the alkynyl group display doublets a t 110.62 and 66.60 ppm with P-C coupling constants of 4.1 and 14.7 Hz, respectively. The 31P(1H} NMR spectrum contains a singlet a t 13.9 ppm along with the corresponding tin satellites. In agreement with the trans disposition of the tricyclohexylphosphine and stannyl ligands the values of the P-'17Sn and P-llgSn coupling constants are 908.8 and 968.6 Hz, respectively.
3492 Organometallics, Vol. 14, No. 7, 1995
Complex 21 can be also prepared in quantitative yield by addition of 1 equiv of HSnPh3 to a NMR tube containing a benzene46 solution of 13. Similarly, the addition of 1 equiv of HSn"Bu3 to an NMR tube containing 13 quantitatively yields 22 (eq 4).
Table 3. Hydroetannation of Phenylacetylene" yield, %b [prod], catalyst
M
cisPhCH=CH(SnPhs)
15 19 21
0.084 0.052 0.054
15 60 60
transPhCH-CH(SnPh3) 85 40 40
a [Catalyst] = 1 x M; [hydroquinone] = 4 x M; [PhC+Hl = [HSnPhd = 0.1 M; n-octane (0.125 M)is used as internal standard. Solvent: 1,2-dichloroethane. Argon atmosphere, temperature 60 "C. Time of reaction 20 min. In presence of hydroquinone (4x M)and in absence of catalyst no reaction occurs. In absence of catalyst and hydroquinone the reaction gives the trans product. The relative amount of each product was measured in the lI9Sn spectra.
13
PCY3 R = Ph (21), "Bu (22)
Complex 22 was characterized by 'H, 31P{1H}, and 13C{lH} NMR spectroscopy. The 'H NMR spectrum of the solution formed by addition of one equiv of HSn"BUQto a benzene-& solution of 13 shows in the higher field region, at -9.80 ppm, a doublet with a P-H coupling constant of 15.7 Hz, along with the satellites due to the tin isotopes. The value of the Sn-H coupling constant, 32.7 Hz, is in agreement with the structure shown in eq 4. The most noticeable signals in the l3C{lH) NMR of this solution are those corresponding t o the C, and Cp carbon atoms of the alkynyl ligand, which appear at 108.89 and 69.65 ppm. The first signal as a singlet and the second one as a doublet with a P-C coupling constant of 15.7 Hz. The 31P{1H}NMR spectrum contains a singlet a t 11.1 ppm along with the satellites due to the l17Sn and l19Sn isotopes. In accordance with a mutually trans disposition for the phosphine and stannyl ligands, the values of the P-l17Sn and P-'lgSn coupling constants are 641.9 and 671.7 Hz, respectively. Under off-resonanceconditions, the singlet is split into a doublet as a result of the P-H coupling. The IR spectrum of the solution formed by addition of 1equiv of HSn"Bu3 to a dichloromethane solution of 13 shows between 2200 and 1900 cm-l four bands. Two strong absorptions at 2035 and 1995 cm-l, assigned to the vibration v(C0) of two carbonyls ligands mutually cis disposed and two weak absorptions at 2135 and 2110 cm-l, assigned to the vibrations v(Ir-H) and v(C=C), respectively. The oxidative addition of silanes t o iridium(1) complexes is generally viewed as a concerted cis addition.23 Furthermore, Johnson and Eisenberg have proved that the addition of HSiR3 t o the iridium(1) cis-phosphine complexes IrX(CO)(dppe)(X = Br, CN; dppe = 1,2-bis(dipheny1phosphino)ethane)is a diastereoselective process with specific substrate ~ r i e n t a t i o n .The ~ ~ exclusive and quantitative formation of 19-22,with the hydrido and stannyl ligands mutually cis disposed, is also in agreement with a concerted cis addition of HSnPha and HSn"Bu3 to 9 and 13,with specific substrate orientation. The addition of HSnPhs and HSn"Bu3 to 9 seems to take place along the olefin-Ir-P axis with the tin (23)(a)Sommer, L. H.; Lyons, J. E.; Fujimoto, H. J. Am. Chem.
SOC.1969,91, 7051. (b)Harrod, J. F.; Smith, C. A.; Than, K. A. J.Am. Chem. SOC. 1972, 94, 8321. (c) Fawcett, J. P.; Harrod, J. F. J . Organomet. Chem. 1976, 113, 245. (d) Bennet, M. A,; Charles, R.; Fraser, P. J. Aust. J. Chem. 1977, 30, 1201. (24)Johnson, C. E.; Eisenberg, R. J. Am. Chem. SOC.1985, 107,
6531.
Esteruelas et al.
atom on the olefinic bond (A),and the oxidative addition t o 13 seems to occur along the OC-Ir-P axis with the tin atom on the carbonyl group (B). The basis of this preference is probably steric and involves minimizing nonbonded interactions between the stannyl ligand and the cyclohexyl groups of the phosphine. SnR3
H
A
SnR3
H
B
Addition of HSnPb to Phenylacetylene Catalyzed by IrH2(SnPhs)(TFB)(PCys),IrH(C2Ph)(SnPhs)(TFB)(PCys), and IrH(C2PW(SnPb)(CO)2(PCys). The complexes IrHz(SiEts)(TFB)(PR3)(PR3 = PCy3, PiPr3, PPh3) catalyze the addition of HSiEts to phenylacetylene in 1,2-dichloroethane at 60 "C, to give PhCH=CH2, cis-PhCH=CH(SiEts), trans-PhCH=CH(SiEtd, Ph(SiEts)C=CHz, and PhC=C(SiEts). The major product, about 65%, in almost all cases is cisPhCH=CH(SiEts), resulting from anti addition of the silane to the alkyne. Under the same experimental conditions the related dihydrido-stannyl compound 14 catalyzes the addition of HSnPh3 to phenylacetylene. In this case, the major product is trans-PhCH=CH(SnPhd (Table 31, resulting from syn addition of the stannane to the alkyne. The formation of the dehydrogenative stannylation product, PhC1CSnPh3, is not observed. We note from our previous reports that the formation of the dehydrogenative silylation product takes place when the cis-vinylsilane is an important product of the catalytic r e a c t i ~ n . A~ recent , ~ ~ ~study ~ ~ on the addition of HSiEt3 to phenylacetylene catalyzed by [Ir(COD)(V2'Pr2PCH2CH2OMe)lBF4 reveals that the hydrido-alkynyl [I~H(C~P~)(COD)(V~-'P~~PCH~CH~OM~)IBF~ is the key intermediate for the formation of PhClCSiEt3 while [IrH(SiEt3)(COD)(y2-iPr2PCH2CH20Me)lBF4 is the key intermediate in the formation of c ~ s - P ~ C H = C H ( S ~ E ~ ~ ) . ~ ~ So, one could think that, for some systems, the formation of the anti-addition product is favored by the presence of transition metal-alkynyl compounds. (25) Esteruelas, M. A,; L6pez, A. M.; Oro, L. A,; Tolosa, J. I. J. Mol. Catal., A. Chem. 1995, 96, 21. (26) Esteruelas, M. A,; Olivan, M.; Oro, L. A,; Tolosa, J. I. J. Organomet. Chem. 1995,487, 143.. (27) (a) Fernandez, M. J.; Oro, L. A.; Manzano, B. R. J. Mol. Catal. 1988,45,7. (b) Jun, C. H.; Crabtree, R. H. J. Organomet. Chem. 1993, 447, 177.
Square-Planar IridiumU) Compounds In order to find some relationship between the presence of metal-alkynyl compounds and the formation of the dehydrogenative stannation and anti-addition products, in the hydrostannation of terminal alkynes, we have explored the catalytic activity of the alkynyl derivatives 19 and 21 in the hydrostannation of phenylacetylene with HSnPhs. Although under these conditions the formation of the dehydrogenative stannation product is not observed, the results presented in Table 3 clearly show that in the presence of the alkynyl derivatives 19 and 21, the amount of the anti-addition product (cis-PhCH=CH(SnPhs)) formed is important (60%). At this moment additional work is carried out in our laboratory, in order to determine whether the presence of a transition metal-alkynyl compound can affect the formation of the anti-addition product in the hydrosilylation and hydrostannation of terminal alkynes.
Concluding Remarks This study has shown that the reaction of the compounds Ir(XR)(TFB)(PCyd(XR= OMe, OEt, O R , OPh, SnPr)with HSnR'3 leads to the dihydridostannyl derivatives IrH2(SnR'3)(TFB)(PCy3) ( R = Ph, "Bu). In the solid state, these compounds have an octahedral structure with the stannyl group and the phosphine ligand occupying pseudo-trans positions (for SnR3 = SnPh3, Sn-Ir-P = 129.45(3)").In solution, they have a rigid structure only at low temperature; at room temperature an intramolecular exchange process takes place which involves the relative positions of the diolefin atoms. The values for M and AS* of the fluxional processes are in agreement with a mechanism involving the dissociation of one arm of the diene, followed by rotation of the diolefin around of the other iridium-olefin bond. The square-planar alkynyl compounds Ir(C2Ph)Lz(PCy3) also react with HSnR3 to afford IrH(C2Ph)(SnR'dLdPCy3) (L2 = TFB, 2CO; R' = Ph, n B ~ )These . reactions are diastereoselective cis addition processes with specific substrate orientation. The complexes IrHz(SnPh3)(TFB)(PCy3),IrH(C2Ph)(SnPhd(TFB)(PCya) and IrH(CzPh)(SnPh3)(C0)2(PCyd catalyze the addition of HSnPh3 to phenylacetylene to give cis- and trans-PhCH=CH(SnPh3). Interestingly, the formation of the dehydrogenative stannation product is not observed. This is in contrast with that previously reported for related hydrosilylation reactions, in which the formation of P h C ~ c S i E t 3accompany to the formation of the syn- and anti-addition products.
Experimental Section General Data. All reactions were carried out with the use of standard Schlenk procedures. Solvents were dried and purified by known procedures and distilled under argon prior to use. Elemental analyses were performed with a PerkinElmer 240 microanalyzer. 'H, 13C{'H}, 31P{1H}, and llgSn NMR spectra were recorded on Varian UNITY 300 or Varian XL 200 spectrometers. Chemical shifts are expressed in parts per million upfield from SiMe4 ('H and 13C{1H)NMR spectra), 85% H3P04 (31P{1H}NMR spectra), or SnMe4 (lI9Sn NMR spectra). Infrared spectra were obtained from a Perkin-Elmer 783 spectrophotometer, as either solids (Nujol mulls on polyethylene sheets) or solutions (NaC1 cell windows). The catalytic reactions were followed by measuring the phenylacetylene consumption as a function of time using n-octane
Organometallics, Vol. 14, No. 7, 1995 3493 as the internal standard with a FFAP on Chromosorb GHP 80/100 mesh column at 170 "C. Mass spectra analyses were performed with a VG Auto Spec instrument. In FAB+ mode (used for complexes 6 and 7) ions were produced with the standard Cs+ gun at ca. 30 kV, and 3-nitrobenzyl alcohol (NBA)was used as the matrix. Electron impact MS (operating at 70 eV) was used for MeOSnPh3, 'PrOSnPha, PhOSnPh3, and "PrSSnPh3. The starting material Ir(OMeMTFB)(PCy3)(1)was prepared by published method.28 Preparation of Ir(OEt)(TFB)(PCys)(2). A suspension of 1 (100mg, 0.137 mmol) in 5 mL of ethanol was stirred for 1h at room temperature. The solution was decanted, and the orange solid was washed with ethanol and dried in vacuo; yield 67 mg (66%). Anal. Calcd for C32&4F4IfiP C, 51.68; H, 5.96. Found: C, 52.17; H, 6.66. IR (Nujol, cm-'): v(C-0) 1055 (m). 'H NMR (c&, 20 "0:6 5.31(br, 2H, -CHI, 4.12 (q,2H, JH-H = 6.7 Hz, OCHzCHd, 3.58 (br, 2H, =CHI, 2.00-1.10 (m, 35 = 6.7 Hz, OCH2CHs; this signal H, -CH, Cy), 1.40 (t, 3H, JH-H is partially masked by c y resonances). 31P{1H}NMR (CsD6, 20 "C): 6 19.0 ( 8 ) . Preparation of Ir(O'Pr)(TFB)(PCyd(3). A suspension of 1 (100 mg, 0.137 mmol) in a mixture of acetone/2-propanol 1:lO (11mL) was stirred for 1h at room temperature, and the suspension was concentrated to dryness. Acetone was added to afford an orange solid, the solution was decanted, and the solid was washed with acetone and dried in vacuo; yield 74 mg (71%). Anal. Calcd for C33H46F4IrOP: C, 52.30; H, 6.12. Found: C, 52.53; H, 6.65. IR (Nujol, cm-'1: v(C-0) 1125 (m). 'H NMR (CsD6,20 "C): 6 5.26 (br, 2H, -CH), 3.73 (sept, lH, JH-H = 5.9 Hz, OCH(CH3)2), 3.55 (br, 2H, =CH), 2.00-1.10 = 5.9 Hz, OCH(CH3)2; (m, 35 H, -CH, Cy), 1.36 (d, 6H, JH-H this signal is partially masked by Cy resonances). 31P{1H} NMR (c&3,20 "c): 6 18.8 (S). Preparation of Ir(OPh)(TFB)(PCyd(4). A suspension of 1 (100 mg, 0.137 mmol) in 10 mL of acetone was treated with a n excess of PhOH (52 mg, 0.55 mmol). The resulting suspension was stirred for 2 h at room temperature. After concentrating to dryness, acetone was added to afford an orange solid. The solution was decanted, and the solid was washed with acetone and dried in vacuo; yield 63 mg (58%). Anal. Calcd for C36H44F4IrOP: C, 54.60; H, 5.60. Found: C, 54.21; H, 5.48. IR (Nujol, cm-I): v(C=C, Ph) 1590 (s), v(C0 ) 1255 ( 6 ) . 'H NMR (CsD6, 20 "C): 6 7.26-6.78 (m, 5H, Ph), 5.09 (br, 2H, -CHI, 3.44 (br, 2H, =CH), 1.96-1.07 (m, 35H, =CH, Cy). 31P{1H}NMR (C&, 20 "C): 6 19.6 (s). Preparation of IrZ(CO)e(PCy&(5). A solution of 2 (200 mg, 0.27 mmol) or 3 (204 mg, 0.27 mmol) in 8 mL of CHzClz was stirred under CO atmosphere for 30 min. The resulting pale yellow solution was concentrated to ca. 0.5 mL, and addition of hexane precipitated a pale yellow solid. The solution was decanted, and the solid was washed with hexane and dried in vacuo; yield 75 mg (40%). Anal. Calcd for C42H~Ir206P~: C, 45.31; H, 5.97. Found: C, 45.68; H, 6.24. IR (Nujol, cm-I): v(C0) 1940 (vs). IR (CHZC12, cm-'): v(C0) 1945 (vs). 31P{1H} NMR (CsD6, 20 "C): 6 21.1 (9). MS (FAB+): mle 1056 (M+ - 2CO), 557 (M+/2). Preparationof Ir(SnPr)(TFB)(PCys) (6).This compound was prepared analogously as described for 4, starting from 1 (100 mg, 0.137 mmol) with an excess of "PrSH (0.5 mL). Compound 6 was isolated as an orange microcrystalline solid: yield 93 mg (82%). The crystals contained 1 mol of acetonel mol of 6. Anal. Calcd for C36H52F41rOPS: C, 51.96; H, 6.30. Found: C, 52.48; H, 7.19. 'H NMR (C&, 20 "C): 6 5.28 (br, 2H, -CH), 3.46 (br, 2H, =CHI, 2.59 (t, 2H, JH-H = 7.1 Hz, SCHZCH~CH~), 2.00-1.09 (m, 40 H, -CH, Cy, SCHZCHZCH~). 31P{1H}NMR (C6D6, 20 "C): 6 16.7 (s). Preparation of an Isomeric Mixture of [IrQ-BPr). (CO)(PC~S)]Z (7). This compound was prepared analogously as described for 5, starting from 6 (100 mg, 0.12 mmol). (28) Esteruelas, M. A.; Lahoz, F. J.; Olivan, M.; Ofiate, E.; Oro, L. A. Organometallics 1994,13, 3315.
3494 Organometallics, Vol. 14, NO. 7, 1995 Compound 7 was isolated as an orange solid: yield 54 mg (78%). Anal. Calcd for C44H&-202P2Sz:C, 45.88; H, 7.00. Found: C, 45.96; H, 7.16. IR (Nujol, cm-'): v(C0) 1955-1935 (vs). IR (CH2C12, cm-1): v(C0) 1945 (vs), 1930 (vs). MS (FAJ3+): mle 1151 (M+). Data for 7a are as follows. 'H NMR = (C&, 20 "c): 6 3.80 (m, 2H, SCH2CH2CH31, 2.99 (t, JH-H 7.5 Hz, SCH2CH2CH3), 2.40-0.86 (m, 76H, PCy3 and SCH2CH2CH3). 31P{1H}NMR (C6D6, 20 "c): 6 29.1 (9). Data for 7b are as follows. 'H NMR (c&, 20 "c): 6 3.25 (m, 4H, SCH~CHZCH~), 2.40-0.86 (m, 76H, PCy3 and SCH~CHZCH~). 31P{1H}NMR (C&, 20 "c): 6 30.9 (SI. Preparation of Ir(CaPh)(TFB)(PCys)(9). PhCrCH (14 pL, 0.137 mmol) was added to a suspension of 1 (100 mg, 0.137 mmol) in 10 mL of acetone, The resulting red solution was stirred for 1 h at room temperature and cooled at -20 "C for 24 h. The solution was decanted, and the brown-red solid was washed with acetone and dried in vacuo; yield 72 mg (66%). Anal. Calcd for C38H~F41rP: C, 57.05; H, 5.54. Found: C, 56.90; H, 5.78. IR (Nujol, cm-l): v(CsC) 2080 (s), v(C=C, Ph) 1595 (SI. 'H NMR (C6D6, 20 "c): 6 7.63-6.94 (m, 5H, Ph), 5.32 (br, 2H, -CH), 4.12 (br, 2H, =CH), 2.52 (br, 2H, =CHI, 2.15-1.09 (m, 33H, cy). l3C{lH) NMR (C&, 20 "c): 6 130.91 (s, Ph), 128.89 (s, Cp, CEC), 128.39 (s, Ph), 125.56 (9, Ph), 125.05 (d, Jp-c = 12.9 Hz, C,, CEC), 62.84 (d, Jp-c = 11.9 Hz, CH=), 45.32 (s, CH=), 40.93 (s, -CHI, 35.50 (d, Jp-c = 26.7 , (d, Jp-c = 10.6 Hz, Hz, PCH, PCy,), 30.62 (s, P C Y ~ )27.99 (s, PCs.3). 31P{1H}NMR (C6D6, 20 "c): PCHCH2, P C Y ~ 26.79 ), 6 23.2 (SI. Preparationof Ir(C&y)(TFB)(PCys)(10). CyCrCH (18 pL, 0.137 mmol) was added to a suspension of 1 (100 mg, 0.137 mmol) in 10 mL of acetone. The resulting red solution was stirred for 4 h at room temperature and concentrated to 5 mL, yielding a brown-red solid. The solution was decanted, and the solid was washed with acetone and dried in vacuo; yield 77 mg (70%). Anal, Calcd for C38HsoFJrP: C, 56.63; H, 6.25. Found: C, 57.05; H, 6.69. 'H NMR (C&, 20 "c): 6 5.30 (br, 2H, -CH), 4.10 (br, 2H, =CHI, 3.00 (br, l H , CWCH), 2.39 (br, 2H, =CH), 2.20-1.19 (m, 43H, Cy). 13C{'H} NMR (C&, 20 "C): 6 133.50 (s, Cij, CEC), 111.10 (d, Jp-c = 12.6 Hz, Ca, C=C), 62.41 (d, Jp-c = 12.4 Hz, CH=), 42.02 (s, CH=), 40.71 (s, -CH), 35.47 (s, Cy), 35.39 (d, Jp-c = 25.7 Hz, PCH, PCyd, 27.99 (d, Jp-c = 10.6 Hz, PCHCH2, PCY~), 26.91 30.57 (s, PCY~), (s, Cy), 26.83 (s, Cy), 26.76 (s, PCY~), 25.55 (s, Cy). 31P{'H} NMR (C6D6, 20 "c): 6 22.5 (SI. Preparation of Ir(CzCO&le)(TFB)(PCys) (11). This compound was prepared analogously as described for 9, starting from 1 (100 mg, 0.137 mmol) and Me02CCrCH (12 pL, 0.137 mmol). Compound 11 was isolated as a red solid: yield 44 mg (41%). Anal. Calcd for C34H42F4Ir02P: C, 52.23; H, 5.41. Found: C, 52.45; H, 5.69. IR (Nujol, cm-'1: v(C=C) 2065 (s), v(C=O) 1680 (6). 'H NMR (C6D6, 20 "c): 6 5.20 (br, 2H, -CH), 3.87 (br, 2H, =CH), 3.46 (5, 3H, -C02CH3), 2.62 (br, 2H, =CH), 2.03-1.15 (m, 33H, Cy). 13C{'H} NMR (C6D6, 20 "C): 6 154.24 (9, -CO&H3), 129.71 (d, JP-c = 12.0 Hz, Ca, CaC), 119.72 (s, Cp, CsC), 63.65 (d, Jp-c = 11.5 Hz, CH=), 51.04 (s,-C02CH3), 50.13 (9, CH=), 40.97 (s, -CHI, 35.48 (d, Jp-c = 26.5 Hz, PCH, PCys), 30.56 (s, PCyd, 27.79 (d, JP-c= 10.7 Hz, PCHCH2, PCy,), 26.69 (s, PCy3). 31P{1H}NMR (C6D6, 20 "C): 6 23.9 (s). Preparation of Ir(C&iMes)(TFB)(PCys) (12). This compound was prepared analogously as described for 10, by starting from 1 (100 mg, 0.137 mmol) and Me3SiCsCH (19.4 pL, 0.137 mmol). Compound 12 was isolated as a brown-red solid; yield 50 mg (46%). Anal. Calcd for C35H48F4IrPSi: C, 52.81; H, 6.08. Found: C, 52.47; H, 6.23. IR (Nujol, cm-'): v(C=C) 2020 (s). 'H NMR (CsD6, 20 "C): 6 5.25 (br, 2H, -CHI, 4.02 (br, 2H, =CH), 2.54 (br, 2H, =CH), 2.10-1.19 (m, 33H, Cy), 0.38 (s, 9H, -SiMe3). 13C{'H} NMR (CDC13, 20 "C): 6 143.76 (d, Jp-c = 11.5 Hz, C,, CEC), 131.14 (s, Cij, C&), 62.06 (d, Jp-c = 12.0 Hz, CH=), 47.69 (s, CH-), 40.70 ( 8 , -CH), 34.86 ), (s, P C Y ~ 27.67 ), (d, Jp-c (d, J p - c = 26.2 Hz, PCH, P C Y ~ 30.14
Esteruelas et al. = 10.6 Hz, PCHCH2, PCyd, 26.40 (s, PCy31, 1.50 (s, -SiMea). 31P{1H}NMR (C6D6, 20 "C): 6 22.6 (s). Preparation of Ir(CzPh)(CO)z(PCys)(13). A solution of 9 (100 mg, 0.125 mmol) in 8 mL of CHzClz was stirred under CO until the color of the solution change from deep red to yellow (2 min). The solution was concentrated to ea. 0.5 mL, and addition of hexane caused the precipitation of a yellow solid. The solution was decanted, and the solid washed with hexane and dried in vacuo; yield 52 mg (66%). Anal. Calcd for C28H38Ir02P: C, 53.40; H, 6.08. Found: C, 53.75; H, 6.55. IR (Nujol, cm-'1: v(C=C) 2100 (m), v(C0) 2045 (s), 1970 (vs), v(C=C, Ph) 1590 (m). IR (CH2C12, cm-'1: v(C0) 2050 (s), 1980 (vs). 'H NMR (CDC13,20 "C): 6 7.39-7.15 (m, 5H, Ph), 2.601.20 (m, 33H, Cy). 31P{1H}NMR (CDC13, 20 "C): 6 27.6 (SI. Preparation of IrHz(SnPb)(TFB)(PCys)(14). A solution of 1(100 mg, 0.137 mmol) in 6 mL of toluene was treated with HSnPh3 (96 mg, 0.274 mmol), and an immediate color change from orange to pale yellow was observed. This solution was stirred for 30 min at room temperature. The solution was concentrated to ea. 0.5 mL, and addition of hexane caused the precipitation of a white solid. The solution was decanted, and the solid was washed with hexane and dried in vacuo; yield 134 mg (938). Anal. Calcd for C48Hb5F4IrPSn: C, 54.92; H, 5.28. Found: C, 55.09; H, 5.51. IR (Nujol, cm-'): v(1r-H) 2118 (m), 2093 (m); v(Sn-Ph) 253 (s). 'H NMR (C6D6, 20 " 0 : 6 8.01-7.22 (m, 15H, Ph), 4.88 (br, 2H, -CHI, 3.11 (br, 4H, = 20.1 Hz, =CH), 1.85-1.04 (m, 33H, Cy), -15.37 (d, 2H, JP-H Ir-HI. 'H NMR (C7D8, -60 "C): 6 4.88 (br, l H , -CH), 4.82 (br, l H , -CH), 3.22 (br, 2H, =CH), 2.77 (br, 2H, =CHI, the other resonances are the same as that at 20 "C. 31P{1H}NMR (C6D6,20 "C): 6 14.8 (s with tin satellites, J p - 1 1 9 ~= ~ 737.0 Hz, J p - 1 1 7 ~= ~ 641.8 Hz; triplet in off-resonance). MS (EI) analysis of the mother liquors shows the presence of MeOSnPh3. Mass fragmentation pattern of MeOSnPh3: 382 (M+),351 (M+ - 31, Ph3Sn), 274 (M+ - 108, PhzSn), 197 (M+ - 185, SnPh). This complex may also be prepared from 3 (100 mg, 0.132 mmol; yield 102 mg (74%)),4 (100 mg, 0.126 mmol; yield 102 mg (77%)),and 6 (100 mg, 0.12 mmol; yield 101 mg (80%))as starting materials. MS (EI) analysis of the mother liquors show the presence of 'PrOSnPh3, PhOSnPhs, and "PrSSnPhs, respectively. Mass fragmentation pattern of 'PrOSnPhs: 380 (M+ - 30, Ph3SnOCH),351 (M+ - 59, PhsSn), 274 (M' - 136, PhzSn), 197 (M' - 213, SnPh). Mass fragmentation pattern of PhOSnPhs: 444 (M+), 351 (M+ - 93, PhsSn), 197 (M+ 247, PhzSn). Mass fragmentation pattern of "PrSSnPha: 426 (M+), 383 (M+ - 43, PhaSnS), 351 (M+ - 75, PhaSn), 274 (M+ - 152, PhzSn), 229 (M+ - 197, PhSnS), 197 (M+ - 229, PhSn). Preparation of IrH2(SnnBus)(TFB)(PCys) (15). This compound was prepared analogously as described for 14, starting from 1 (100 mg, 0.137 mmol) and HSn"Bu3 (74 pL, 0.274 mmol). Compound 15 was isolated as a white solid: yield 79 mg (57%). Anal. Calcd for C4&sF41rPSn: C, 50.91; H, 6.92. Found: C, 50.79; H, 6.98. IR (Nujol, cm-'): v(1r-HI 2102 (m). 'H NMR (C6D6, 20 "c): 6 5.10 (br, 2H, -CH), 3.00 (br, 4H, =CHI, 2.00-1.10 (m, 60H, Cy, "Bu), -15.98 (d, 2H, Jp-H 21.3 Hz). 'H NMR (C~DB, -60 "C): 6 5.19 (br, l H , -CH), 4.87 (br, l H , -CHI, 3.21 (br,2H, -CHI, 2.61 (br, 2H, =CHI, the other resonances are the same as that at 20 "C. 3lP{lH} NMR (C&, 20 "C): 6 13.1(s with tin satellites, J p - 1 1 9 ~ ~ = 528.4 Hz, Jp-L17Sn = 504.1 Hz; triplet in off-resonance). Reaction of 14 with CO: Formation of Ir(SnPh)(CO)s(PCys). A solution of 14 (100 mg, 0.095 mmol) in dichloromethane (10 mL) was stirred under CO atmosphere during 16 h. The solution was concentrated t o ea. 0.5 mL, and addition of hexane precipitated a white solid. The solution was decanted, and the solid was washed with hexane and dried in vacuo; yield 60 mg (70%). IR (Nujol, cm-'1: v(C0) 1950 (vs), v(Sn-Ph) 260 (s). IR (CH2C12, cm-'1: v(C0) 1945 (s). 'H NMR (c&)6,20 "C): d 8.10-7.10 (m, 15H, Ph),1.90-0.90 (m, 33H, Pcy3). 31P{1H}NMR (C6D6, 20 "C): 6 21.9 (s with tin satellites, Jp-llgsn = 584.0 Hz, J p - 1 1 7 ~=~ 560.0 Hz).
Square-Planar IridiumU) Compounds Preparation of IrH(C2Ph)(SnPh)(TFB)(PCy3) (19). A solution of 9 (100 mg, 0.125 mmol) in 6 mL of toluene was treated with HSnPha (4.4mg, 0.125 mmol), and a n immediate color change from red to light yellow was observed. The solution was stirred for 15 min and concentrated to ea. 0.5 mL. Addition of methanol precipitated a white solid. The solution was decanted, and the solid was washed with methanol and dried in vacuo; yield 119 mg (83%). Anal. Calcd for C5&IsoF41rPSn: C, 58.44; H, 5.25. Found: C, 58.16; H, 5.15. IR (Nujol, cm-'): v(Ir-H) 2113 (s), v(C=C) 2058 (m), v(CpC, Ph) 1599 (m), v(Sn-Ph) 246 (SI. 'H NMR (C6D6, 20 "c): 6 8.22-6.85 (m, 20H, Ph), 5.21 (br, lH, -CH), 4.98 (br, lH, -CH), 3.72 (br, l H , =CH), 3.47 (br, lH, =CHI, 3.42 (br, lH, =CH), 2.43-1.01 (m, 34H, =CH and PCy3), -13.32 (br, 1H; this resonance is a doublet with JP-H = 21.6 Hz in the 'H NMR spectrum at -60 "C in toluene-&). l3C{lH] NMR (&De, 20 "C): 6 145.18 (d, JP-c= 5.5 Hz, CipsoSnPhd, 137.95 ( 8 , SnPhd, 131.53 (s, Ph), 131.49 (s, Ph), 128.41 (s, SnPha), 128.24 (s, SnPh3), 128.13 (overlapping, Ph), 125.58 (s, Ph), 109.01 (br, Cp,C=C, this signal was only observed in the spectrum at -60 "C), 72.30 (d, Jp-c = 17.5 Hz, Ca, C W ) , 43.90 (br S, CH=), 39.80 (br s, CH-1, 37.59 (d, Jp-c = 21.6 Hz, PCyd, 36.25 (br s, CH-), 36.10 (br s, CH=), 30.68 (s, PCy,), 29.95 (6, PCyd, 28.15 (d, Jp-c = 11.5 Hz, PCY~), 28.00 (d,J p - c = 11.5 Hz, PCY~), 26.97 (s, PCy3). 31P{'H} NMR (C&, 20 "c): 6 -1.9 (6 with Sn satellites, Jp-1L9Sn = 735.6 Hz, J P - I=~715.9 ~s~ Hz, doublet in off-resonance). Preparation of IrH(CzPh)(Sn"Bus)(TFB)(PCys)(20). This compound was prepared analogously as described for 19, starting from 9 (100 mg, 0.125 mmol) and HSn"Bu3 (34 pL, 0.125 "01). Compound 20 was isolated as a white solid: yield 101 mg (74%). Anal. Calcd for CsoH~zF41rPSn:C, 55.04; H, 6.93. Found: C, 55.37; H, 6.43. IR (Nujol, cm-l): v(1r-H) 2085 (s), v(C=C) 2020 (m), v(C=C, Ph) 1590 (m). 'H NMR (C&, 20 "C): 6 7.39-6.87 (m, 5H, Ph), 5.31 (br, 1H, -CH), 5.08 (br, lH, -CHI, 3.54 (br, lH, =CHI, 3.31 (br, lH, .-CHI, 3.21 (br, l H , =CHI, 2.30 (br, l H , =CH), 2.20-1.04 (m, 60H, "Bu, Cy), -13.68 (d, lH, J p - H = 26.1 Hz, J s n - = ~ 28.6 Hz, IrH). 13C{lH} NMR (C6D6, 20 "c): 6 131.23 (s, Ph), 131.20 (s, Ph), 129.28 (s, Ph), 129.24 (s, Ph), 125.21 (s, Ph), 107.29 (d, Jp-c = 3.7 Hz, Cp, CEC), 76.95 (d, JP-c= 18.4 Hz, Ca, CSC), 37.80 (br s, CH-1, 37.40 (br s, CH-1, 37.36 (d, Jp-c = 19.8 Hz, PCy3), 36.57 (br s, CH=), 35.85 (br s, CH-), 31.03 (s, "Bu), 30.55 (s,PCy,), 29.77 (s,PCys), 28.25 (s, "Bu), 28.18 (d, J p - c = 10.6 Hz, PCY~), 27.09 (s,PCy,), 14.13 (s,"Bu), 13.49 (s,"Bu). 31P{1H} NMR (C6D6, 20 "C): 6 -2.0 (s with Sn satellites, JP-l19Sn = 550.5 Hz, J p - 1 1 7 ~ ~= 525.9 Hz, doublet in offresonance). Preparation of ~H(CSh)(SnP43)(CO)2(pCys)(21). This complex can be prepared by using two different procedures. (a) To a 5 mm NMR tube containing a solution of 13 (50 mg, 0.079 mg) in 0.5 mL of benzene-& was added HSnPhs (28 mg, 0.079 mg). After 2 h, lH and 31P{1H} NMR spectra were recorded. (b)A solution of 19 (100 mg, 0.087 mmol) in CHzC12 (10 mL) was stirred under CO for 30 min, and the pale yellow solution was concentrated to ca. 0.5 mL. Addition of hexane caused the precipitation of a white solid. The solution was decanted, and the solid was washed with hexane and dried in vacuo; yield 64 mg (75%). Anal. Calcd for C46H5411'0zPSn: c, 56.33; H, 5.50. Found: C, 55.93; H, 5.68. IR (Nujol, cm-'): v(Ir-H) 2140 (w), v(C=C) 2110 (s), v(C0) 2040 (SI, 2000 (s). IR (CH2C12, cm-'1: v(Ir-H) 2130 (w), v(C=C) 2115 (w), v(C0) 2050 (s), 2000 (S). 'H NMR (C6D6, 20 "c): d 8.06-6.82 (m, 20H, Ph), 2.20-1.10 (m, 33H, Cy), -9.42 (d, l H , JP-H 14.8 Hz, Js,,-H = 29.0 Hz, Ir-H). 13C{lH} NMR (CsD6, 20 "c): 6 173.09 (br, CO), 171.22 (d, JP-c= 4.6 Hz, CO), 143.96 (d, JP-c = 6.9 Hz, ClPwSnPha), 137.70 (s, SnPha), 131.45 (s, Ph), 131.42 (s, Ph), 128.58 (s, Ph), 128.18 (9, SnPha), 127.85 (8, SnPha), 125.88 (s, Ph), 110.62 (d, Jp-c = 4.1 Hz, C,J, CSC), 66.60 (d, Jp-c = 14.7 Hz, Ca, CsC), 34.78 (d, JP-c = 22.5 Hz, PCya), 29.68 (s,PCY~), 29.60 (s, PCY~), 27.59 (d, JP-c= 10.1 Hz, PCY~), 27.49 (d, Jp-c = 10.6 Hz, PCys), 26.56 (S,Pcy3). 31P{1H)NMR (c&,
Organometallics, Vol. 14, No. 7,1995 3495 Table 4. Atomic Coordinates (A x 104; x106 for Ir, P, and Sn Atoms) and E uivalent Isotropic x 10s; xlO4 for Ir, P, Displacement Coefficients and Sn Atoms) for the Compound fiKdSnPhs)(TFB)(PCys)(14) atom nla Ylb ZIC U,.
(la
11352(2) 22318(3) -2945( 11) 4756(3) 4883(3) 3251(4) 1442(3) 3919(5) 3995(5) 3170(5) 2244(5) 2176(5) 3027(5) 1300(5) 2148(5) 2988(5) 2853(5) 1417(5) 570(5) -1021(5) - 1542(6) -1952(6) -2900(6) -2373(7) -2013(5) 517(4) 892(5) 1496(6) 2687(6) 2330(6) 1713(5) -1621(5) -2454(5) -3322(6) -4181(6) -3411(7) -2513(5) 2551(5) 3778(6) 3945(7) 2898(7) 1673(6) 1510(5) 4069(5) 4498(6) 5586(7) 6256(7) 5869(8) 4769(7) 1123(6) 1645(7) 955W -246(9) -805(7) - 116(6)
6968(2) -12779(3) 27301(11) -2318(3) -1430(3) 850(3) 2256(3) -1181(5) -747(5) 410(5) 1131(4) 702(4) -480(4) 1402(4) 1576(4) 394(5) -784(4) -695(5) 489(5) 3831(4) 5301(5) 6061(6) 554546) 4094(6) 3335(5) 3804(4) 3336(5) 4310(6) 4519(6) 4956(5) 4006(5) 2572(5) 1685(6) 1398(6) 2657(6) 3604(6) 3853(5) -3190(4) -3975(6) -5205(6) -5622(6) -4832(6) -3638(5) -1247(5) -124(7) -51(9) - 1148(10) -2257(9) -2330(7) -1438(5) - 1399(6) -1586(7) -1803(7) -1822(7) -1639(6)
29050(1) 22762(2) 24942(6) 492 l(2) 6054(2) 6332(2) 5484(2) 5043(3) 5631(3) 5770(3) 5327(3) 4745(2) 4601(2) 4184(2) 3452(2) 3314(3) 3922(3) 3929(2) 4080(2) 3149(2) 2853(3) 3456(3) 4052(4) 4340(3) 3740(3) 1748(2) 1030(2) 462(3) 666(3) 1366(3) 1951(3) 209.1(3) 2556(3) 2133(4) 1783(4) 1329(4) 1743(3) 2986(3) 3082(4) 3559(4) 3937(3) 3863(3) 3391(3) 1607(3) 1365(3) 850(4) 568(4) 789(4) 1312(4) 1535(3) 817(3) 349(4) 581(4) 1291(4) 1753(3)
a Equivalent isotropic U defined as one-third of the trace of the orthogonalized Ug tensor.
20 "C): 6 13.9 (s with Sn satellites, J p - 1 1 9 ~=~968.6 Hz, J P - L ~ ~ S ~ = 908.8 Hz).
Preparation of IrH(CSh)(SnnBus)(C0)2(PCys)(22). This compound was prepared analogously as described for 21 (method a), startingfrom 13 (50 mg, 0.079 mmol) and HSn"Bu3 (21 pL, 0.079 mmol). IR (CHzC12, cm-'): v(1r-H) 2135 (w), v(C=C) 2110 (w), v(C0) 2035 (s), 1995 ( 8 ) . 'H NMR (C6D6,20 "C): 6 7.53-6.92 (m, 5H, Ph), 2.24-0.97 (m, 60H, "Bu, Cy), -9.80 (d, lH, J p - H = 15.7 Hz, Js"-H = 32.7 Hz, Ir-HI. 13C{'H} NMR (C& 20 "c): 6 175.00 (s, co), 173.28 (s, co),131.41 (s, Ph), 128.97 (6, Ph), 125.65 (s,Ph), 108.89 ( 8 , C/j, c@), 69.65 (d, Jp-c = 15.7 Hz, Ca, C=C), 34.80 (d, Jp-c = 21.1 Hz, PCyd, 30.99 (s, SnnBu3), 29.86 (s, PCya), 29.60 ( 8 , Pcyd, 27.87 (s,
