Electro-inorganic synthesis: a convergent paired electrochemical synthesis and voltammetric studies of copper(II)-2-aminophenol derivatives

Electrochemical reduction of 2-nitrophenol and 5-methyl-2-nitrophenol has been studied in water/ethanol mixture using cyclic voltammetry and controlled-potential coulometry. Our voltammetric data indicate the formation of 2-aminophenol (HLI) and 5-methyl-2-aminophenol (HLII), respectively. Also, the electrochemical synthesis of copper(II) complex of 2-aminophenols has been carried out using copper metal as a sacrificial anode and lead metal as a cathode in water/ethanol (50/50 v/v). The electrochemical synthesis of copper(II)-2-aminophenols consists of a multi-step such as (a) cathodic reduction of 2-nitrophenols to related 2-aminophenols, (b) generation of Cu2+ from copper anode, (c) complexation of 2-aminophenols with Cu2+. In this work, we have proposed a mechanism for the electrode process. Some parameters such as electrode material, current density, electricity passed and temperature, were also systematically studied. The convergent paired electrochemical synthesis of copper(II) complex of 2-aminophenols has been successfully performed in a one-pot process, under constant current condition in an undivided cell, in a good yield and purity. Also, the electrochemical behavior of copper(II)-2-aminophenol complex was studied and the stability constant of copper(I)-2-aminophenol complex was evaluated using cyclic voltammetry.