Organolutetium Complexes in σ-Bond Metathesis Reactions Involving Silicon. Catalysts for the Hydrogenolysis of Si−C Bonds

The lutetium hydride complex [Cp*₂Lu(μ-H)]₂ (1) efficiently cleaves the Si−C bond of PhSiH₃ to produce benzene and cross-linked polysilanes (SiH_x)_y. The Si−C bond cleavage appears to proceed via the lutetium phenyl complex Cp*₂LuPh (2). This is supported by the reaction of PhSiH₃ with 2, which results in the formation of benzene. Moreover, activation of the Si−C bond of C₆F₅SiH₃ by 1 yields the related lutetium aryl complex Cp*₂LuC₆F₅ (4) and oligosilanes. The reaction of 1 with o-MeOC₆H₄SiH₃, on the other hand, results in the formation of dihydrogen and the neutral lutetium silyl complex (5). The solid-state structure of 5 was determined by X-ray crystallography. Reactions of arylsilanes with the lutetium methyl complex [Cp*₂LuMe]₂ (3) are less selective than the corresponding reactions of 1 and lead to competitive Si−C and Si−H bond activations. Complex 1 acts as an efficient catalyst for organosilane hydrogenolysis. Thus, addition of excess phenyl- or hexylsilane to solutions of 1 under an atmosphere of dihydrogen at 75 °C results in formation of benzene or hexane, respectively, along with cross-linked polysilanes.