Electrochemistry of copper complexes with macrocyclic polyamines containing pyrazole units

Abstract

The voltammetric behaviour of bi- and mono-nuclear complexes formed in solution by Cu²⁺ with three polyazacyclophanes containing pyrazole units in aqueous solution is described. Cyclic and square wave voltammetric responses at glassy carbon electrodes indicate that the reduction of copper–macrocycle complexes in solution takes place in two successive one-electron per Cu transfer processes coupled with preorganization and protonation reactions that mimic the behaviour of superoxide dismutase. The electrochemistry of ternary Cu²⁺–receptor–dopamine complexes exhibits significant differences with respect to the protection of the neurotransmitter from post-electron transfer cyclization reactions.