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 frag ment 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 met alloid 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.