Homoleptic bisterpyridyl complexes: Synthesis, characterization, DNA binding, DNA cleavage and topoisomerase II inhibition activity

Octahedral complexes of type [Co(L)(2)]center dot 2NO(3) 1, [Co(L)(2)]center dot 3NO(3) 2 and [Zn(L)(2)]center dot 2NO(3) 3 (L = 4'-phenyl-2,2': 6',2 '' terpyridine) are synthesized and characterized using elemental analysis, NMR, IR, UV-Vis and fluorescence spectra and further supported by their X-ray diffraction studies. The binding properties of the complexes with DNA are carried out using UV-Vis, fluorescence titrations. Viscosity measurement supported partial intercalation of the complexes with DNA. Gel electrophoretic mobility assay of the complexes with Plasmid DNA (pBR322) shows that complex 1 binds with the major groove of double helical DNA. The molecular docking showed that complex 1 binds to DNA via groove binding in GC-rich sequence. It also inhibits topoisomerase II activity with IC50 value as 30. Other complexes do not bind DNA significantly. (C) 2015 Elsevier B.V. All rights reserved.