Preparation and characterization of mercapto-bridged homo- and hetero-binuclear palladium platinum complexes

Abstract

Reaction of [Pd 2(μ-Cl) 2Cl 2(PR 3) 2] (R = Pr n, Bu n or Ph) with mercaptans in acetone yields dimercapto bridged binuclear palladium complexes, [Pd2(μ- SR′) 2Cl 2(PR 3) 2] (R′ = Et or Pr i) ( I), which on treatment with [M 2(μ-Cl) 2Cl 2(PR 3) 2] (M = Pd or Pt) in chloroform affords homo- or hetero-binuclear complexes of the type [PdM(μ-SR′)(μ-Cl)Cl 2(PR 3) 2] (M = Pd ( II) or Pt ( III)). In addition to III, homo- binuclear complexes, [Pt 2(μ-SR′) 2Cl 2(PR 3) 2], [Pd 2- (μ-Cl) 2Cl 2(PR 3) 2] and [M 2(μ-SR′)(μ-Cl)Cl 2(PR 3) 2] were also formed. Treatment of III with R′SH in acetone yields another series of stable hetero- binuclear complexes, [PdPt(μ-SR′) 2Cl 2(PR 3) 2] ( IV), (R = Pr n or Bu n; R′ = Et or PR i). The NMR data ( 1H and 31P{ 1H}) indicate that complexes I and IV exist in a sym—cis configuration while II and III have a structure in which phosphine ligands are trans to the bridging chloride. A few bridge cleavage reactions with pyridine, PPh 3, AsPh 3 have also been investigated by 31P{ 1H} NMR spectroscopy.