Lability criteria for metal complexes in micro-electrode voltammetry

Abstract

Theoretical expressions are derived for the voltammetric lability criteria of metal complexes in the micro-electrode regime. The treatment includes three limiting situations: (i) the macro-electrode limit, where both the diffusion layer and the dissociation reaction layer are linear; (ii) an intermediate case with a hemispherical diffusion layer and a linear reaction layer; and (iii) the micro-electrode limit with hemispherical diffusion and reaction layers. The results show that the operational lability of complexes will generally decrease with decreasing electrode size in going from (i) to (ii), but that it increases again when (iii) is approached. Results for some types of metals with different kinetic characteristics are presented.