Electrochemical and density functional theory studies of some newly synthesized azo-stilbene chromogenic structures

Abstract

The electrochemical behavior in nonaqueous media of a series of five newly synthesized azo-stilbene dyes is investigated with the aim of elucidating the anodic oxidation mechanism of the latter to gain a better understanding of potential oxidative degradation phenomena to find new and environmentally sustainable electrochemical methods for the abatement of dyes from industrial wastewater. In addition, the frontier orbital energies of optimized conformers have been computed using quantum chemical calculations at the B3LYP-D3 (dispersion corrected Becke, 3-parameter, Lee Yang Parr) level of theory. Cyclic voltammetry experiments show that anodic oxidation of the studied chromophore structures follows an irreversible pathway and most probably occurs at the amide nitrogen. Validation of experimental results has been conducted by computation of various global reactivity descriptors, confirming that substituents grafted on the benzene ring actively influence the oxidation/reduction potentials.