ChemInform Abstract: On the Nature of Electroactive Sites in Clay-Modified Electrodes.

ChemInform Abstract

The electrochemical properties of montmorillonite clay films deposited on pyrolytic graphite electrodes have been studied by cyclic voltammetry. The results demonstrate unequivocally that tris(bipyridyl) metal complexes and methylviologen cations bound electrostatically to the exchange sites of montmorillonite are rigorously electroinactive. However, these films incorporate ML3²⁺ (M: Fe, Ru, Os;L: bpy) and methylviologen cations from solution and exhibit voltammetric responses characteristic of diffusional processes. The electroactivity for films immersed in ML3²⁺ and methylviologen solutions is attributed in part to cations which are bound at the clay surface in excess of the cation exchange capacity by an ion pairing mechanism.