DNA/protein binding, cytotoxicity and catecholase activity studies of a piperazinyl moiety ligand based nickel(II) compleX

The Ni(II) complex, {[Ni(HL)(SCN)(2)(H2O)].2(DMF)} (1) [HL = 6-methoxy-24[2-(1-piperazinyl)ethylimino] methyl)phenol], was synthesized and characterized by X-ray crystal structure analysis and spectroscopic methods. The crystal structure of complex 1 reveals a distorted octahedral coordination geometry around the nickel centre which forms a supramolecular assembly through hydrogen bonds. The interaction of complex 1 with the calf thymus DNA (CT-DNA) was investigated using electronic absorption and fluorescence spectroscopic methods. The results show that complex 1 has binding affinity to CT-DNA in the order of 6.06 x 10(5) M-1. The interactions of complex 1 with bovine serum albumin (BSA) and human serum albumin (HSA) were also studied using electronic absorption and fluorescence spectroscopic techniques and the analysis show that interaction of complex 1 with BSA/HSA occur mainly with ground state association process. The number of binding sites and binding constant were calculated using double logarithm regression equation. Anticancer activity of 1 in human breast (MCF7) cancer cell lines reveals dose dependent suppression of cell viability with IC50 value 64 +/- 3.7 mu M. Catecholase activity of 1 has been investigated in methanol medium using 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the result shows that 1 is active for catalyzing aerobic oxidation of 3,5-DTBC to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ). (C) 2016 Elsevier Ltd. All rights reserved.