Synthesis and Characterization of a Mononuclear Schiff-Base Copper Complex and Its Activity towards Benzyl Alcohol Oxidation

Abstract

In this work, Schiff base derived copper complex was synthesized using N,N'-(ethane-1,2-diyl)bis(1-(pyridin-2-yl)methanimine) ligand and a copper perchlorate salt as a source for copper. The electronic spectroscopy revealed a weak d-d transition band (621nm). The electrochemical characterization of copper complex revealed one cathodic event at Epc1 = −0.343 V vs Ag/AgNO3 and two anodic events at Epa1 = −0.189 V and Epa2 = +0.220 V vs Ag/AgNO3, respectively. The two events at −0.343 V and −0.189 V formed a redox couple with a peak separation of 154 mV. The ratio of ipc1 / ipa1 = 0.24 and ∆Epa = 154 mV suggested that the redox couple is quasi-reversible in nature. The copper complex with TEMPO as a nitroxyl radical and NMI as a base was used to study the oxidation of benzyl alcohol at different loading quantities of catalyst which suggested that the copper complex is only stoichiometrically oxidizing benzyl alcohol to corresponding aldehyde.