Ruthenium Amidinato−Carbene Complexes Containing a Ru−Si Bond:  Formation and Reversible α-Silyl Group Migration from the Metal to the Carbene Ligand

Reactions of the coordinatively unsaturated complexes [(eta (6)-C6Me6)Ru{eta-(PrNC)-Pr-i(Me)=(NPr)-Pr-i}]X-+(-) with Me3SiCHN2 resulted in the formation of the amidinato-carbene complexes [(eta (6)-C6Me6)Ru{=(CHNPrC)-Pr-i(Me)=N-i-Pr}(SiMe3)]X-+(-), in which a trimethylsilyl group is bonded to the ruthenium atom. Migration of the silyl group to the carbene ligand occurred on reaction with CO, whereas the reverse reaction was promoted by photochemical dissociation of CO.