The advantages of organic redox mediators over traditional inorganic counterparts are availability; they may in the future enlarge their applicability in all systems involving electron transfer during electrochemical processes. Several quinones, diphenoquinones and respective reduced forms, hydrobenzoquinones and hydrodiphenoquinones, were synthesized, and their electrochemical properties were studied by cyclic voltammetry to access their upcoming applicability as organic redox mediators.

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 (E ⁰) at E ⁰ = −0.53 V and E ⁰ = −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 E _pc = 0.31 V and E _pa = 1.00 V versus SCE.