REACTIONS OF TRIMETHYL GROUP IVA HALIDES (Si,Ge, Sn) WITH PHOSPHINE-BRIDGED PALLADIUM,PLATINUM, AND SILVER DIMERS

Abstract

Reactions of a series of binuclear, phosphine bridged late transition metal complexes, Pd₂Cl₂(dppm)₂, Pd₂Cl₂(dmpm)₂, Pd₂Cl₂(Ph₂Ppy)₂, Pt₂Cl₂(dppm)₂, and Ag₂Br₂(dppm)₂, with Me₃SiX (X = Br, I), Me₃GeBr and Me₃SnBr were examined by ³¹P NMR spectroscopy. Rapid exchange of Pd-Cl, Pt-Cl and Ag-Br bonds for Pd-X, Pt-X (X = Br, I) and Ag-I bonds was observed to be independent of the nature of the phosphine ligand, the nature of the metal center or the group IV element. Differences in Lewis acidity of the transition metal center as a function of the ligands and the identity of the transition metal and differences in the basicity of the Me₃EBr ligands are proposed to account for the failure to detect intermediates in these reactions similar to those reported for reactions between Pd₂Cl₂(dppm)₂ and Me₃SiX.