Complex-formation reactions of dichloro(L-methioninato)-palladium,(II) with inosine and inosine 5′- monophosphate. Labilization induced by the S-donor chelate

Abstract

The kinetics and mechanism of the complex-formation reactions of [Pd(met)Cl₂]^–(met =L-methionine anion) with inosine and inosine 5′-monophosphate were studied in detail as a function of the chloride and nucleophile concentrations, temperature and pressure in weakly acidic aqueous solutions. Two consecutive reaction steps which both depend on the nucleophile concentration were observed. A comparison with rate data for the corresponding ethylenediamine and substituted ethylenediamine complexes reveals the significant lability induced by the S-donor chelate in [Pd(met)Cl₂]^–. The reported activation parameters underline the operation of an associative ligand-substitution mechanism under all conditions.