Kinetics of base hydrolysis of cationic dichlororhodium(III) complexes containing two substituted ethylenediamine ligands

Abstract

The kinetics of base hydrolysis of complexes of the type trans-[Rh(L–L′)₂Cl₂]⁺(L–L′= en, men, sdmen, udmen, trimen, or tetmen) have been studied and found, with the exception of the complex with L–L′= tetmen, to depend on [OH^–]. For the complexes with L–L′= en or udmen the observed pseudo-first-order rate constant is given by k_obs. =k₁+k₂[OH^–] for hydroxide-ion concentrations up to 1.0 mol dm^–3, whereas no [OH^–]-dependent term occurs for the complex with L–L′= tetmen over the same range of [OH^–]. The activation parameters for the base hydrolysis of the complexes with L–L′= en, udmen, or tetmen have been determined and are discussed in relation to literature data for the base-hydrolysis reactions of similar amine chlororhodium(III) complexes and some analogous cobalt(III) complexes.