Reactions of Carbon Monoxide with Trimethylsilyl and Tris(trimethylsilyl)silyl Derivatives of Group 4 Metals. Synthesis, Characterization, and Reactivity of Silaacyl Complexes

摘要

Numerous unsaturated molecules are catalytically or stoichiometrically reduced by transition-metal silane systems. The degree to which insertions into M-Si bonds contribute to this reactivity is unclear, since few insertions involving metal-silicon bonds have been directly observed. Insertion of carbon monoxide has long been considered unfavorable, since attempts to carbonylate metal silyl derivatives have previously failed. This low reactivity toward insertions is consistent with observations that transition-metal-silicon bonds are shorter than expected, presumably strengthened by pi bonding between the transition metal and silicon. Our studies concerned with early transition-metal-silyl reactivity have included reactions with carbon monoxide in order to elucidate the factors involved in silyl migration to coordinated CO.