Synthesis, Crystal Structure, Spectroscopic, Thermal, Catechol Oxidase and Catalase-Like Studies: New Copper(II) Complexes of 2-Benzoylbenzoate and 2-Pyridilpropanol Ligands

Abstract

Two novel copper(II) complexes, mononuclear [Cu(bba)<inf>2</inf>(pypr) <inf>2</inf>] 1 and dinuclear [Cu<inf>2</inf>(bba)<inf>2</inf>(pypr) <inf>2</inf>] 2, have been synthesized by reactions of 2-pyridilpropanol with CuSO<inf>4</inf>·5H<inf>2</inf>O or Cu(CH<inf>3</inf>COO) <inf>2</inf>·2H<inf>2</inf>O metal salt in the presence of 2-benzoylbenzoic acid. The copper(II) ion has a distorted octahedral geometry in 1 and distorted square pyramidal geometry in 2. 1 crystallizes in space group P1̄, while 2 crystallizes in the monoclinic crystal system with the space group P2<inf>1</inf>/n. 2-Benzoylbenzoate behaves as a monodentate in 1, bidentate in 2. 2-pyridilpropanol ligand acts as a bidentate in 1 and bridging in 2. Both complexes were characterized by elemental analysis, mass and IR spectroscopy. Their molecular structures were determined by X-ray crystal structure analysis and their thermal stabilities were confirmed by TG/DTA/DTG techniques. Dinuclear compound shows high catalytic activity regarding the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone exhibiting saturation kinetics at high substrate concentrations. In addition, dinuclear compound demonstrates significantly catalase-like activity. But mononuclear complex shows neither catalase-like nor catechol oxidase activity.© 2012 Elsevier B.V. All rights reserved.