Dinuclear copper(II) complexes bridged with acetate and nitrate anions: Study of protein binding and in-vitro anticancer activity

Two dinuclear copper(II) complexes [Cu(L)(mu-AcO)(2)](2)center dot H2O (1) and [Cu(L)(bpy)(mu-NO3)](2). (ClO4)(2) (2) were synthesized with the ligand L = N-(3-pyridyl)-1,8-naphthalimide (where, OAc = Acetate, bpy = 2,2 '-bipyridine). The complexes were characterized with FT-IR, UV-vis, fluorescence, EPR, and single crystal X-ray diffraction technique. Complex 1 contains two copper(II) units bridged by four acetate ions via oxygen atoms having dis-torted square pyramidal geometry around both the copper(II) centers. Complex 2 consists of two copper(II) centers with two bridging nitrates via oxygen atoms in a distorted square pyramidal environment. The complexes 1 and 2 efficiently bind to BSA (bovine serum albumin) showing a dynamic quenching mechanism. The in-vitro anticancer activity have been investigated against HeLa cell lines using MTT assay. Complex 1 is two times more active than cisplatin under the same experimental conditions, whereas complex 2 is twelve times more active.