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 (SiHx)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.