A comparative evaluation of the voltammetric behaviour of phenyl methyl sulfone, phenyl methyl sulfide and phenyl methyl sulfoxide in N, N-dimethylformamide on a glassy carbon electrode

Abstract

Detailed voltammetric studies of PhSO₂Me, PhSOMe and PhSMe in DMF containing 0.1 mol dm^–3 TBAP media on glassy carbon electrodes indicate significant weak adsorption of all three sulfur compounds. Weakly adsorbed species also get reduced in the same potential region where solution species are reduced. Comparative studies indicate a significantly higher apparent ‘n’ value of 2.2 ± 0.2 for PhSOMe when compared to 1.7 ± 0.2 for the other two compounds. Formation of phenyl sulfinate at the same potential during PhSOMe reduction is confirmed by the oxidation wave in reverse sweep. A modified disproportionation reaction scheme involving [PhSOMe]^– radical anion leading to the formation of [PhSMe]^2– and [PhSO₂Me] is proposed. Since the dianionic sulfide species undergoes fast, irreversible dissociation, the reduction peak due to this sulfide species is not observed at more negative potential. An interaction between PhS^– species and PhSOMe species is also indicated by the anodic voltammetric response.