The Osmium–Silicon Triple Bond: Synthesis, Characterization, and Reactivity of an Osmium Silylyne Complex

The first silylyne complex of a metal beyond group 6, [Cp*((i)Pr3P)(H)Os≡Si(Trip)][HB(C6F5)3], was prepared by a new synthetic route involving hydride abstraction from silicon. NMR and DFT computations support the presence of a silylyne ligand, and NBO and ETS-NOCV analysis revealed the nature of this Os-Si interaction as a triple bond consisting of a covalent σ bond and two strong π back-donations. The discovery of this complex allowed observations of the first cycloadditions involving a silylyne complex, and terminal alkynes are shown to react via C-H bond additions across the Os≡Si bond.