pH Dependent Electrochemistry of Anthracenediones at a Glassy Carbon Electrode

Abstract

© The Author(s) 2015.The voltammetric response of 1-hydroxy-2(hydroxymethyl)anthracene-9,10-dione (HAC) and 1,8-dihydroxy-4,5-dinitro anthracenedione (DHDN) was investigated at a glassy carbon electrode in acidic, neutral and basic media by cyclic, square wave and differential pulse voltammetry. The oxidation of DHDN was evidenced by the appearance of one irreversible and two reversible peaks in the square wave voltammograms. The shift of peak potentials with change in pH demonstrated proton coupled electron transfer reactions. DHDN exhibited two steps pH dependent reduction while HAC reduced in a single step involving two electrons and two protons. The square wave voltammetric response showed the quasi-reversible nature of the reduction process of HAC. However, its oxidation followed irreversible behavior. The results of sensitive voltammetric techniques helped in proposing the electrode reaction mechanism of HAC and DHDN. Moreover, physical parameters such as diffusion coefficient, pKa and electron transfer rate constant were determined from scan rate, pH and concentration effects.