Electrochemical Oxidation of Disulfides Derived from Isocyanuric Acid

Abstract

Anodic oxidation of linear and bicyclic disulfides derived from isocyanuric acid was studied by cyclic voltammetry and numerical simulation. The PM3 molecular modeling revealed three types of the highest occupied molecular orbitals determining the electrochemical reactivity of these compounds: n electrons of the sulfur atoms of the disulfide bridge in linear and N-Me- and N-Ph-substituted bicyclic disulfides, π electrons of the aromatic fragment in the disulfide with the N-2-(2-methoxyphenoxy)ethyl isocyanurate substituent, and n electrons of the sulfide sulfur atoms in the compound with the -SS- and -S- fragments in the aliphatic chain. Oxidation of the disulfides with the SS-localized highest occupied molecular orbital follows the scheme with reversible electron transfer, followed by a fast potential-determining second-order reaction and a slow current-determining first-order reaction (ECC mechanism). The isocyanurate heterocycle does not participate directly in redox transformations but stabilizes the electrochemically generated radical cations by the mechanism of transannular interaction.