Steric effects in substitution reactions of cis- and trans-arylchlorobis-(triethylphosphine)platinum(II) complexes: new kinetic data for the approach to the problem of transition-state geometry

Abstract

The rate of displacement of Cl^– ion in the complexes trans- and cis-[Pt(PEt₃)₂(R)Cl](R = Ph, o-MeC₆H₄, and 2,4,6-Me₃C₆H₂) with CN^– has been studied in propan-2-ol containing 6% water. Analysis of the relative reactivity of the two sets of isomers gives some indication of the configuration of the transition state. It is shown that literature data concerning reactions of the same systems with pyridine (py) in ethanolic solution are incorrect. The trans-complexes do not undergo bimolecular attack and the cis-complexes spontaneously isomerize to the trans-form before or during their reaction with py.