Reactions of Diruthenium Tetrahydride Complex (η⁵-C₅Me₅)Ru(μ-H)₄Ru(η⁵-C₅Me₅) with Vinylsilanes:  Formation of a μ-Silylene Complex via Successive Si−H and Si−C Bond Cleavage of Dimethylvinylsilane

The diruthenium complex {Cp*Ru(μ-H)} 2 {μ-η 2:η 2 -HSiMe 2 (CH CH 2 )} ( 5a; Cp* = η 5 -C 5 Me 5 ) containing a μ-vinylsilane ligand was prepared by the reaction of Cp*Ru(μ-H) 4 RuCp* ( 1 ) with dimethylvinylsilane. The μ-η 2:η 2 -coordination mode of dimethylvinylsilane was confirmed by means of 1 H, 13 C, and 29 Si NMR and IR spectroscopy. The Si−C(sp 2 ) bond of 5a was readily cleaved upon thermolysis with liberating hydrogen and resulted in formation of the μ-silylene, μ-ethylidyne complex (Cp*Ru) 2 (μ-SiMe 2 )(μ-CCH 3 )(μ-H) ( 8 ) via the μ-silyl, μ-vinyl complex (Cp*Ru) 2 (μ-η 2 -HSiMe 2 )(μ-η 2 -CH CH 2 ) ( 9a ) as an intermediate. The reaction of 1 with trimethylvinylsilane rendered cleavage of both Si−C(sp 2 ) and Si−C(sp 3 ) bonds, which resulted in formation of 8 . Treatment of 8 with carbon monoxide led to formation of the μ-ethylidene complex by migration of the hydride to the bridging carbon; thus {Cp*Ru(CO)} 2 (μ-CHMe)(μ-SiMe 2 ) ( 10 ) was obtained. The reaction of 8 with ethylene afforded the μ-vinyl, μ-silylene complex (Cp*Ru) 2 (μ-η 2 -CH CH 2 )(μ-SiMe 2 )(μ-H)(CH 2 CH 2 ) ( 11 ). The reaction of 8 with molecular hydrogen resulted in a re-formation of 1 with liberating dimethylethylsilane, which showed formation of the Si−C bond on the dinuclear system. The molecular structures of 5a, 8, and 10 were determined by single-crystal X-ray diffraction studies.