Preparation and characterization of some mixed ligand complexes of platinum(II)

Abstract The mixed ligand complexes PtX 2 (ER 3 )L and PtXY(ER 3 )L (where ER 3 = PR 3 or AsMe 3 ; L = phosphine, arsine; X = Cl; Y = Cl, H or Me) have been prepared and characterized. Reaction of PtMe 2 (ER 3 )L with HCl yields PtMeCl(ER 3 )L, in exclusively one of three possible isomeric forms. Excess tetramethyltin reacts with Pt 2 Cl 2 (μ-Cl) 2 (PMe 2 Ph) 2 giving both cis and trans Pt 2 (μ-Cl) 2 (PMe 2 Ph) 2 , as identified from the NMR spectra. Cleavage of Pt 2 (μ-Cl) 2 Me 2 (PMe 2 Ph) 2 with donor ligands such as AsPh 3 , PMe 2 or pyridine, was useful as a synthetic route to the unsymmetrical methylchloro Pt II derivatives. The reaction of cis -[PtMe 2 (PPh 3 )(AsPh 3 )] with excess dimethylacetylenedicarboxylate (DMA) yielded only one product, which was of the formula trans -[Pt{C(COOCH 3 )C(COOCH 3 )CH 3 } 2 (PPh 3 )(AsPh 3 )], with the alkenyl groups having the same geometry about the CC bond. The use of diethylacetylene-dicarboxylate (DEA) rather than DMA gave a similar product. However, when cis -[PtMe 2 (PEt 3 )(AsPh 3 )] was allowed to react with DMA, two products of the formula trans -[Pt{C(COOCH 3 )C(COOCH 3 )CH 3 } 2 (PEt 3 )(AsPh 3 )] were obtained, with the stereochemistry of both alkenyl groups being either cis or trans .