Determination of the Oxidation Potentials of Pyrogallol and Some of Its Derivatives: Theory and Experiment

The Oxidation potentials of pyrogallol and some of its derivatives in aqueous solutions have been calculated. The calculations have been performed using ab initio molecular orbital calculations (HF), and density functional theory (DFT) with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The polarizable continuum model is used to describe the solvent. It was also obtained experimentally with the aid of an electrochemical technique (cyclic voltammetry). The theoretical and experimental values for the oxidation potential of the studied pyrogallol and some derivatives are in excellent agreement with each other and there is only a discrepancy of 0.025 V and 0.020 V for B3LYP and HF methods, respectively, between experimental and theoretical results. The agreement mutually verifies the accuracy of the experimental method and the validity of the applied mathematical model.