Electrochemical oxidation of hydantoins at glassy carbon electrode

The electrochemical behavior of three new hydantoin derivatives; 5-benzylideneimidazolidine-2,4-dione (NBI), 5-(2hydroxybenzylidene)imidazolidine-2,4-dione (HBI), and 5-(4methoxybenzylidene)imidazolidine-2,4-dione (MBI) has been examined over the pH range 1.2–12.8 via cyclic, differential pulse and square wave voltammetry at the surface of glassy carbon electrode. The results of anodic peak potential shift as a function of pH revealed that NH moiety is oxidized by a 1e−, 1H+ diffusion controlled process. The quasi-reversible nature of the redox process was evidenced by Epa − Epa/2 values, scan rate variation of peak potential, heterogenous electron transfer rate constant and inequality of the components of total current. The pKa values of the studied hydantoins were found in good agreement with the reported related structures and varied in the sequence: MBI > NBI > HBI. The variation of diffusion coefficients also followed the same order. Based upon the results obtained, oxidation mechanisms were proposed with the objective of highlighting important aspects of structure–activity relationships and understanding the unexplored pathways by which this class of compounds exert its biochemical actions.

► The electrode reaction mechanism of novel hydantoins has been established.
► Thorough electrochemical science of hydantoins has been convincingly discussed.
► Sensitive modern electrochemical techniques were used for the investigation of hydantoins in a wide pH range.
► The compounds were found to oxidize in a pH dependent, quasi-reversible and diffusion controlled process involving the same number of electrons and protons.
► The computational and experimental results were found in very good agreement.