Syntheses of Di- and Trinuclear Platinum Complexes with Multibridged Germanium Centers Derived from Unsymmetrical Digermanes

Abstract

A trigonal-bipyramidal Pt3Ge2 cluster was synthesized by the reaction of the zerovalent platinum complex [Pt(dppe)(η2-C2H4)] (dppe = 1,2-bis(diphenylphosphino)ethane) with the unsymmetrical digermane H3GeGeEt3 at a 3/2 molar ratio. The platinum centers formed a triangular plane bridged by two germylyne ligands, one of which maintained the Ge–Ge bond. To investigate the Pt3Ge2 cluster formation process, the phenyl-substituted digermanes HPh2GeGeMe3 and H2PhGeGeR3 (R = Me, Et), in which two hydrogen atoms and one hydrogen atoms of the reactive GeH3 moiety were replaced by the bulkier phenyl group(s) together with the substitution of the GeEt3 group by a GeMe3 group, respectively, were used to simplify the reaction system. They provided the digermylplatinum hydride [Pt(dppe)(H)(GePh2GeMe3)] (2) and the bis(μ-germylene)diplatinum complexes [Pt2(dppe)2(μ-GeHPh)(μ-Ge(Ph)GeR3)] (3, R = Me; 4, R = Et) in moderate yields, respectively. For 3 and 4, the first-formed digermylplatinum hydride I-1 underwent dissociati...