2015. 56, 2 – UDC 548.73:547.13:546.562 STRUCTURAL CHARACTERIZATION OF A NEW COPPER(II) COMPLEX OF 1,10-PHENANTHROLINE AND BENZOATE [Cu(phen)(C6H5CO2 )2] S.S. Batool1, S. Ahmad1, I.U. Khan2, Ejaz2, W.T.A. Harrison3 1Department of Chemistry, University of Engineering and Technology, Lahore, Pakistan E-mail: saeed_a786@hotmail.com 2Department of Chemistry, Government College University, Lahore, Pakistan 3Department of Chemistry, University of Aberdeen, Aberdeen, Scotland E-mail: w.harrison@abdn.ac.uk Received September, 10, 2013 Revised — August, 6, 2014 A new mixed-ligand copper(II) complex of 1,10-phenanthroline (phen) and benzoate ligands having the general formula [Cu(phen)(C6H5CO2)2] is prepared and its crystal structure is determined by X-ray crystallography. <...> The complex exists in the monomeric form; the coordination environment around the copper(II) ion is square planar, with the pair of monodentate benzoate ligands being in a cis disposition. <...> In the crystal, the molecules are linked into [001] chains by weak C—H O interactions; no aromatic — stacking occurs. <...> Copper containing enzymes perform a number of important functions such as growth, cell differentiation, mitochondrial oxidative phosphorylation (cytochrome C oxidase), catecholamine production (dopamine hydroxylase), pigmentation (tyrosinase), antioxidant protection (superoxide dismutase), anti-inflammatory activity (ceruloplasmin), iron metabolism, and copper transport [ 1—11]. <...> Keeping in view the biological importance of copper complexes, there has been a substantial increase in interest in the study of copper(II) complexes of bipyridine or phenanthroline and carboxylates [20—40 ]. <...> These complexes exhibit a great structural diversity, including mononuclear, binuclear, or even polynuclear supramolecular complexes. <...> In these complexes, carboxylate ions might involve monodentate [20—32 ] and bidentate chelating, including both symmetrical and asymmetrical, coordination modes [32—39 ]. <...> Dicarboxylates usually form polymeric complexes exhibiting monodentate or chelating bridging modes [ 29, 30, 38, 39 ]. — Stacking interactions among the phenantroline ligands and with aromatic carboxylates, and the hydrogen bonding interactions play a very important role in the formation of supramolecular architectures [ 24, 27—30 ]. <...> A considerable number of copper(II) complexes of phenanthroline and monocarboxylic acids (acetic, benzoic, 2-fluorobenzoic, formic, lactic, and propionic <...>