Stable nickel complexes of a siliconoid/silylene hybrid ligand: competent hydrosilylation catalysts for terminal olefins

Abstract

The use of abundant, first row transition metals instead of platinum group metals is a contemporary goal in homogenous catalysis research. Electron-rich silylenes are increasingly established as viable alternatives to carbene-based ligand systems. Here we report that – depending on the first row transition metal fragment employed – a silylene hybridized with a Si₇-siliconoid (Tip₅Si₇NHSi 1) either coordinates to the metal centre via the silylene side-arm exclusively (Fe(CO)₄ complex) and thus retains an unperturbed metalloid core or coordinates in a chelating manner involving the donation by unsubstituted vertices (Ni(cod)-fragment, cod = 1,5-cyclooctadiene). The siliconoid/silylene ligand 1 is bonded more strongly than cod so that the latter is readily replaced by PPh₃ or CO ligands. The cod derivative is catalytically active in the hydrosilylation of terminal olefins with the secondary silane Ph₂SiH₂.