Mechanistic and Thermodynamic Study of Electrochemical Oxidation of 4-Morpholinoaniline in the Presence of Different Nucleophiles

Abstract

In this research electrochemical oxidation of 4-MA in the presence of triphenylphosphine, 1,2-dimethylindole and benzoylacetonitrile were studied both experimentally and theoretically. Cyclic voltammetry and controlled-potential coulometry were used to obtain the experimental results, and the theoretical results were calculated at DFT (B3LYP) level of theory and 6–311+G (p,d) basis set. In the electrochemical oxidation process 4-MA oxidized to its correspond p-quinonediimine (1ox+), and electrochemically generated 1ox+ reacts with nucleophiles. Using voltammetric and coulometric data, it was found that oxidation mechanism of 4-MA in the presence of triphenylphosphine, benzoylacetonitrile and 1,2-dimethyleindole are EC, ECEC and ECECE respectively. ΔGtot of 4-MA and its substituted species were calculated, and results indicate that ΔGtot determines direction of reactions.