The oxidation of cysteine by electrogenerated octacyanomolybdate (v)

Abstract

We report on the response of solid carbon electrodes (glassy carbon and boron doped diamond to the one electron oxidation of octacyanomolybdate(IV) in a wide pH range (1–11). Under alkaline conditions the oxidation of octacyanomolybdate(IV) was found to proceed via a EC reaction mechanism, where one electron oxidation to octacyanomolybdate(V) was followed by inner sphere decomposition of the oxidised species. Further, the electrochemical oxidation of octacyanomolybdate(IV) was studied in the presence of thiols (cysteine, homocysteine and glutathione); an electrocatalytic process occurs, where electrochemically generated octacyanomolybdate(V) species is reduced by cysteine back to the parent octacyanomolybdate(IV) species via a E(C)C′ reaction mechanism. DIGISIM™ modelling was utilised in order to confirm the suggested mechanism and obtain relevant kinetic data.