(HYDROSILYL)TUNGSTEN COMPLEXES OF THE TYPE (C5ME5)(OC)2(ME3P)W-SIR3 (SIR3=SIH3, SI(H)2ME, SI(H)ME2, SI(H)(CL)ME, SI(H)CL2) - SYNTHESIS, CRYSTAL-STRUCTURE, AND DETAILED VIBRATIONAL ANALYSIS

Novel functional silyltungsten complexes of the type (C5Me5)(OC)2(Me3P)W-SiR3 (SiR3 = Si(H)Me2 (3a), Si-(H)(Cl)Me (3b), Si(H)Cl2 (3c)) have been prepared by the reaction of the lithium metalate, Li[W(CO)2(PMe3)C5-Me5] (2), with the corresponding chlorosilanes in cyclohexane. Treatment of 3b,c with LiAlH4 provides the hydrosilyl complexes (C5Me5)(OC)2(Me3P)W-Si(H)2R (R = Me (4a), H (4b)) in remarkably good yields. Spectroscopic properties of 3a-c and 4a,b have been extensively studied by means of NMR, IR, and especially Raman spectroscopy. In addition the crystal structure has been determined for 4a,b. Crystal data for 4a: orthorhombic, Pbca, with a = 14.165 (4) angstrom, b = 15.244 (4) angstrom, c = 18.596 (4) angstrom, V = 4015 (3) angstrom3, Z = 8, R = 0.032, and R(w) = 0.02 1. Crystal data for 4b: orthorhombic, P2(1)2(1)2(1), with a = 8.817 (3) angstrom, b = 14.449 (4) angstrom, c = 15.132 (5) angstrom, V = 1928 (2) angstrom3, Z = 4, R = 0.037, and R(w) = 0.025. The coordination geometry of 4a,b is that of a Cp-capped square pyramid with the silyl and the Me3P ligands in trans positions and a W-Si bond distance of 2.559 (2) angstrom (4a) or 2.533 (3) (4b), respectively.