Electrochemical Studies of Benzoquinone, Hydrobenzoquinone, Diphenoquinone and Hydrodiphenoquinone-Based Compounds

Abstract

Several quinones, diphenoquinones and respective reduced forms, hydrobenzoquinones and hydrodiphenoquinones, were synthesized, and their electrochemical properties were studied by cyclic voltammetry (CV) in non-aqueous medium to assess their upcoming applicability as organic redox mediators. Benzoquinones and diphenoquinones exhibited two reversible electron transfers (ETs) as exemplified by tetra-tert-butyldiphenoquinone, which displayed ETs at standard potential (E0) at E0 = −0.53 V and E0 = −0.92 V versus SCE (saturated calomel electrode). However, hydrobenzoquinones displayed chemically irreversible ET, whereas hydrodiphenoquinones exhibited either chemically irreversible or quasi-reversible ETs. For instance, di-tert-butylhydrobenzoquinone demonstrated two irreversible ETs at Epc = 0.31 V and Epa = 1.00 V versus SCE.