Structure and DNA/BSA binding study of zinc(II) complex with 4-ethynyl-2,2’-bipyridine

In the present study, a zinc(II) complex with 4-ethynyl-2,2’-bipyridine (ebpy), [Zn(ebpy)Cl2], was synthesized and characterized by spectroscopic (1H-NMR, IR and UV–Vis) methods and molar conductivity measurement. The crystal structure of the [Zn(ebpy)Cl2] complex was determined by single-crystal X-ray diffraction analysis, confirming the bidentate coordination of the ebpy ligand through its two nitrogen atoms, while the remaining two coordination sites are occupied by two chloride ions. With the aim to investigate the reactivity of the synthesized zinc(II) complex toward biologically important molecules, its binding affinity to calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) was studied by fluorescence emission spectroscopy. From the obtained results, it can be concluded that [Zn(ebpy)Cl2] complex binds to bovine serum albumin reversibly, while the combination of ethidium bromide (EthBr) and Hoechst 33258 (2’-(4-hydroxyphenyl)-5-[5-(4-methylpiperazine- 1-yl)benzimidazo-2-yl]-benzimidazole) competitive binding study suggests that this complex interacts with ct-DNA through the minor groove binding, which is in agreement with molecular docking study.