NEW MULTICHARGED VIOLOGEN DERIVATIVES .1. ELECTROCHEMICAL-BEHAVIOR IN NAFION FILMS

The electrochemical behaviour of new viologen derivatives, C5V3+ and C5V4+, has been studied in Nafion(R) films on gold electrodes. The new viologens bear extra positive charges with respect to methyl viologen (MV2+). They remain positively charged upon two-electron reduction, while MV2+ is reduced to a neutral form under similar conditions. This fundamental distinction is shown to induce a substantial difference in the voltammetric behaviour and stability of C5V3+ and C5V4+ in Nafion films compared with MV2+. These differences are discussed in terms of a model suggested previously for the electrochemical behaviour of electrode couples comprising neutral/cationic forms in Nafion. The model considers the influence of the inner structure of the polymer on electrochemical reactions occurring therein.