Synthesis and Properties of a Silyl(silylene)ruthenium Complex: Activation Barrier of the RuSi Bond Rotation and Facile Replacement of the Methyl Groups with Alkoxy Groups of a Silyl Ligand

A silyl(silylene)ruthenium complex, Cp*Ru(CO)(SiMes2)SiMe3 (2), was synthesized by the reaction of Cp*Ru(CO)(py)Me with HSiMe2SiMes2Me (Mes = 2,4,6-trimethylphenyl). In contrast to its iron analogue Cp*Fe(CO)(SiMes2)SiMe3 (1), which we reported previously, 2 exhibits a fluxional behavior that involves rotation around the RuSi and Si−C(mesityl) bonds. The activation parameters for the MSi bond rotation were determined for the first time using line-shape analysis of the variable-temperature 1H NMR spectra of 2. Complex 2 underwent a facile alkoxylation reaction on the silyl ligand with ROH (R = Me or Et) in the presence of R′NC (R′ = tBu or Xyl = 2,6-dimethylphenyl) to afford Cp*Ru(CO)(CNR′)[Si(OR)3] and Mes2Si(OR)H in high yields at room temperature, with cleavage of all three Si−C bonds.