Evidence for an almost ‘T-shaped’ co-ordination geometry for carbon in the bis(alkylidene) complex Ta(CH·CMe3)2(2,4,6-Me3C6H2)(PMe3)2: X-ray crystal structure

Abstract

An X-ray structural analysis of the five-co-ordinate species Ta(CH·CMe₃)₂(2,4,6-Me₃C₆H₂)(PMe₃)₂ shows a trigonal bipyramidal arrangement of ligands about the tantalum atom, with the phosphine ligands in axial sites; the Ta–C_α–C_β angles in the two neopentylidene ligands are extraordinarily obtuse, with values of 154·0(6) and 168·9(6)°.