Thermodynamic study of the electrochemical oxidation of some aminophenol derivatives: Experimental and theoretical investigation

Electrochemical oxidation of some aminophenol derivatives (1-5) has been investigated both experimentally and theoretically. Experimental results were obtained using cyclic voltammetry and controlled potential coulometry. The theoretical results were calculated at DFT (B3LYP and BP86) levels of theory and 6-311 + G (p, d) basis sets. Using a general thermodynamic cycle, the calculated Delta G(tot) of the oxidation of the studied aminophenol derivatives indicates that thermodynamic is one of the important parameters on the potential oxidation. The obtained results show that electrochemical oxidation potential of 1-5 is directly dependent on the Delta G(tot) of electrochemical oxidation. In addition in this paper, mechanisms of the electrochemical oxidation of 4-(piperazin-1-yl) phenol (6) in the presence of various nucleophiles was studied in viewpoint of the thermodynamic. Mechanistic study of the electrochemical oxidation of 6 in the presence of different nucleophiles indicates that although the electrochemical oxidations of 6H+ in the presence of different nucleophiles have different mechanisms but proceed in the thermodynamically favored directions. (C) 2014 Elsevier Ltd. All rights reserved.