The ansa-effect in permethyltantalocene chemistry: a [Me2Si] ansa bridge promotes olefin-insertion and reductive-elimination reactions for [Me2Si(C5Me4)2]Ta(η2-C2H4)H and [Me2Si(C5Me4)2]TaH3

Abstract

The ansa-effect, as it applies to tantalocene chemistry, has been investigated by a comparison of the chemistry of [Me₂Si(C₅Me₄)₂]TaH₃ and [Me₂Si(C₅Me₄)₂]Ta(η²-C₂H₄)H with their permethyltantalocene counterparts; these studies demonstrate that incorporation of the [Me₂Si] ansa bridge substantially enhances the rates of both reductive elimination of H₂ and ethylene-insertion into a Ta–H bond.