New copper(II) niflumate complexes with N-donor ligands: Synthesis, characterization and evaluation of anticancer potential against human cell lines

Five new copper(II) niflumate complexes, [Cu(en)(2)(nif)(2)], 1, [Cu(unsym-dmen)(nif)(2)], 2, [Cu(pn)(2)(nif)(2)] [Cu(pn)(2)(H2O)(2)](nif)(2) 3, [Cu(beta-Pic)(2)(nif)(2)], 4, [Cu(gamma-Pic)(2)(nif)(2)] 5 (where en = ethylenediamine, pn = propan-1,3-diamine, unsym-dmen = 1,1-dimethyl-ethylenediamine, beta-pic = 3-methylpyridine, gamma-pic = 4-methylpyridine, nif = niflumate) have been synthesized by using appropriate starting materials and methanol-water (4:1 v/v) as solvent. All the above synthesized complexes 1-5 have been characterized by spectroscopic methods (UV-Vis, FT-IR, and EPR). The structures of complexes 1,3 and 5 have been unambiguously determined by single crystal X-ray structure determination which clearly revealed that these complexes are mononuclear complexes. The structure of complex 4 has been optimized by DFT calculations. In all complexes 1-5, niflumate ligand shows direct coordination to central copper(II) ion leading to covalent character of these complexes, although the complex 3 also contains cationic moiety [Cu(pn)(2)(nif)(2)](2+) and two nifumate ions. The ability of all the complexes to show cytotoxicity against human cancer cell lines has also been evaluated.