Synthesis, crystal structure, cytotoxicity study, DNA/protein binding and molecular docking of dinuclear copper(II) complexes

The Schiff base 2-[(3-Methylamino-propylimino)-methyl]-phenol (HL) has been used for the synthesis of three dinuclear Cu(II) complexes, namely [Cu2L2(dca)(2)] (1), [Cu2L2(2,5-pdc)(2)]center dot 6H(2)O (2), [Cu2L2(tp)] (3), where dca = dicyanamide, 2,5-pdc = pyridine-2,5-dicarboxylate and tp = terephthalate. In 2, HL acts as bidentate (O, N) chelating ligand, while tridentate (O, N, N) in 1 and 3. In all the complexes copper(II) is in its five coordination with distorted trigonal bipyramidal geometry in 1, whereas distorted square pyramidal in 2 and 3. Non covalent interactions give rise supramolecular architectures in all complexes. Cytotoxicity of the complexes was examined using breast cell lines MCF7 and MDA-MB-231. Complexes 1 and 2 show dose dependent suppression of MCF7 and MDA-MB-231 cells and the related IC50 values are 26 +/- 2.9 mu M and 51 +/- 4.7 mu M for MCF7 cell, 16.4 +/- 1.6 mu M and 43.2 +/- 3.1 mu M for MDA-MB-231 cell. Interaction of complexes 1-3 with bovine serum albumin (BSA), human serum albumin (HSA) and calf thymus DNA have been studied by electronic absorption and fluorescence spectroscopic technique. Molecular docking study has been used to explain the interaction of complexes with serum albumins.