Preparation of a zwitterionic trichloroplatinum(II) complex with an alkylbipyridinum ligand and its reaction in dmso-d 6 solution

Abstract

A zwitterionic trichloroplatinum(II) complex PtCl3(4,4′-bpy-N-nBu) (1) was prepared by an aqueous reaction of [4,4′-bpy-N-nBu]Cl with K2PtCl4, and was characterized by 1H-n.m.r. and IR spectroscopy as well as elemental analysis. Dissolving (1) into dmso-d6 at 25 °C yields a mixture of the complexes, cis-PtCl2(4,4′-bpy-N-nBu)(dmso-d6) (2-cis), trans-PtCl2(4,4′-bpy-N-nBu)(dmso-d6) (2-trans), [4,4′-bpy-N-nBu]Cl and PtCl2(dmso-d6)2. Ratio of the products in the dmso-d6 solution changed depending on the temperature and the total concentration of the complexes. These compounds are in equilibrium via isomerization reaction between (2-cis) and (2-trans) and via displacement reaction of the alkylbipyridinium ligand of (2-cis) and (2-trans) with dmso-d6 to form [4,4′-bpy-N-nBu]Cl and PtCl2(dmso-d6)2.