A new type of tungsten(VI) phenylimido alkylidene complex and its triorganotungsten precursor with an O,N-chelating ligand; molecular structures of [W(CH2SiMe3)3(NPh){OCPh2(2-py)}] and [W{CHSiMe3(CH2SiMe3)(NPh){OCPh2(2-py)}](py = pyridine)

Abstract

A new type of tungsten(VI) alkylidene complex has been prepared with [OCPh₂(2-py)], a potentially bidentate O,N-chelating monoanionic ligand, and the corresponding triorganotungsten phenylimido alkoxide precursor complexes have been isolated; the new tungsten(VI) alkylidene complex [W(CHSiMe₃)(CH₂SiMe₃)(NPh)-{OCPh₂(2-py)}]3 reacts with norbornene (70 °C) to provide selectively the cis-polymer in a ring-opening metathesis polymerization reaction.