Electrochemical Oxidation a Series of Ortho Diamines and Predict of Thermodynamic and Kinetic Results Using Density Functional Theory (DFT)

Electrochemical oxidation of 2-aminodiphenylamine (1) in the absence and in the presence of p-TSA was studied using cyclic voltammetry and controlled potential coulometry and the results were reported [1,2]. Voltammetric and coulometric results indicates that 1 is oxidized to it s correspond ortho-quinone diamine (1ox), and the electrochemical generated (1ox) is unstable and reacts with 1 and then corresponding dimer (1a) is produced. It was shown that the oxidation potential of 1a is positive than 1. Also reported results indicates that 1-N-phenyl-4-(sulfonyl) benzene-1,2-diamine (1b) were synthesized during electrolysis of 1 in the presence of p-TSA. The CVs of 1 and 1b indicates that EpA are 0.49 and 0.63 V vs Ag/AgCl respectively [2]. Because species with more positive oxidation potential (EpA1) have larger ∆Gtot values [3], using oxidation potentials of three species 1, 1a and 1b and calculated ∆Gtot of diamine derivatives (2-18), oxidation potentials of them (2-18) were estimated. The recorded cyclic voltammograms (CVs) of 2-aminodiphenylamine (1) show an irreversible feature in low scan rates. In other word because reaction rate of 1 and 1ox is high, a cathodic peak which correspond to the reduction of 1ox to 1 is not visible. Also NBO analysis indicates that a homogeneous reaction rate of the following chemical reaction is related to the charge of the reaction site and increases upon increasing it [4]. Using computational study the positive charge of reaction sites of studied species (1-7) were calculated and rate of dimerization reactions were estimated.