Disproportionation of a halogen-bridged complex containing platinum and palladium

Abstract

³¹ P N.m.r. spectroscopy shows that complexes of the type [PdPtCl₄L_aL_b][L_aand L_b are either the same or different tertiary-phosphide ligands (PPr₃ or Pbu₃)] are formed in chloroform solution when equimolar amounts of [Pd₂Cl₄(L_a)₂] and [Pt₂Cl₄(L_b)₂] are mixed at room temperature. All three complexes are in dynamic equilibrium, and a kinetic study indicates that the exchange occurs via a tetrameric intermediate involving four metal centres. Attempts to isolate the mixed metal complexes have proved unsuccessful. The first measurement of platinum–platinum coupling constants is reported for the complexes [Pt₂Cl₄(PBu₃)₂] and [Pt₂I₄(Pbu₃)₂].