Novel functional silyltungsten complexes of the type (C5Mes)(OC)2(Me3P)W-SiR3 (SiR3 = Si(H)Me2 (3a), Si-

with n-butyllithium, react with HSiCl3 (5) to give C5R5(OC)2(Me3P)M-Si(H)Cl2 (6a-c). Compound 6b is additionally obtained, starting with the tetramethylphosphonium metálate [MeiPlCWfCOMPMeslCsHs] (4), generated from lb with the ylide MesP=CH2 (3). On treatment with L1AIH4, 6a-c undergo smooth Cl/H exchange at the silicon to afford the metallotrihydridosilanes CsRslOCMMesPIM-SiHs (7a-c). The spectroscopic properties of all the compounds have been extensively studied by NMR and IR spectroscopy. In the case of 7a-c, detailed studies of the Raman spectra have been performed as well as force field calculations for the M-S1H3 units, yielding valuable information with respect to Si-H and -Si force constants.

Hydrolysis of organotrichlorosilanes RS1CI3 leads to organosilanetriols RSi(OH)3, which usually undergo rapid condensation to siloxanes.2 When bulky ligands are attached to the silicon, it is possible to isolate and characterize organosilanetriols.3 Recently, the first silanetriols attached to transition metals L"M-Si(OH)3 [L"M = (OC)(Cl)(Ph3P)2Os4 and Cp(OC)2-Fe5] have been obtained from hydrolysis of the corresponding trichlorosilyl complexes, indicating that metal fragments can stabilize silanetriols. The stabilization is derived not only from steric effects of the metal group but also from its electron donation to the silicon. The hydrolysis route is limited by the fact that electron-rich metal fragments reduce substitution rates at silicon, a situation observed for the metallotrichlorosilanes C5R5(OC)2(Me3P)M-

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Synthesis and Reactivity of Silicon