Synthesis and Reactivity of a Dimeric Platinum Phosphinidene Complex

Abstract

The dimeric platinum phosphinidene complex [Pt(dppe)(μ-PMes)] 2 ( 1; dppe = Ph 2 PCH 2 CH 2 PPh 2, Mes = 2,4,6-Me 3 C 6 H 2 ) was prepared by double deprotonation of [Pt(dppe)(μ-PHMes)] 2 [BF 4 ] 2 ( 3 ); use of 1 equiv of base gives the monocationic complex [{Pt(dppe)} 2 (μ-PHMes)(μ-PMes)][BF 4 ] ( 2 ), which can also be made from 1 and 1 equiv of HBF 4 . NMR data suggest that complex 1 contains pyramidal μ-phosphinidene ligands, and it undergoes nucleophilic reactions typical of a tertiary phosphine. Alkylation with MeI affords [Pt(dppe){μ-P(Me)Mes}] 2 [BF 4 ] 2 ( 4 ), BH 3 ·THF gives the borane adduct [Pt(dppe){μ-P(BH 3 )Mes}] 2 ( 5 ), and air oxidation yields [Pt(dppe){μ-P(O)Mes}] 2 ( 6 ). However, reaction with sulfur gives the monomeric trithioxophosphorane complex Pt(dppe)(S 3 PMes) ( 7 ), which was prepared independently from Pt(dppe)( trans -stilbene) and [MesPS 2 ] 2 .