Dissociation kinetics of metal complexes in acid. II. Copper complexes of linear polyamines

Abstract

The acid decomposition kinetics of the monocopper complexes of 20 different linear polyamines have been studied over a range of acid concentrations (0.025 to 0.5 mol dm^-3), I 1.0 (NaNO₃). Complexes which contain only six-membered chelate rings reacted at a rate which is independent of acid concentration. Complexes with five-membered chelate rings have rate constants which show a non-linear dependence on H⁺ concentration. Activation parameters have been determined for some complexes. A mechanism, in which the breaking of the first copper-nitrogen bond or the subsequent protonation of the nitrogen atom is the rate-determining step, is proposed.