Binuclear Schiff base copper(II) complexes: Syntheses, crystal structures, HSA interaction and anti-cancer properties

[Display omitted] •Three binuclear Schiff-base copper(II) complexes were synthesized.•The interaction of these copper complexes with HSA was evaluated.•The anticancer activity of these Cu complexes was evaluated.•Cu(II) complexes induce apoptosis through mitochondrial pathways. Three binuclear Schiff base copper(II) complexes: [Cu2(HL1)2(CH3OH)(NO3)]·NO3 (1), [Cu2(HL2)2(CH3OH)2]·2NO3 (2), and [Cu2(HL3)2(C2H5OH)2]·2NO3 (3) [HL1 = (E)-N′-(5-fluoro-2-hydroxybenzylidene)benzohydrazide, HL2 = (E)-N′-(5-chloro-2-hydroxybenzylidene)benzohydrazide, and HL3 = (E)-N′-(5-bromo-2-hydroxybenzylidene)benzohydrazide], were synthesized and characterized employing various spectroscopic techniques. X-ray crystallography analysis revealed complexes 1–3 to have similar molecular structures. Results from the MTT assay revealed that all copper complexes displayed greater cytotoxicity toward several tumor cell types than cisplatin or the Schiff-base ligands. Further investigations revealed that complex 1 can induce mitochondrion-mediated apoptotic cell death. In addition, the interaction between these Cu(II) complexes and human serum albumin (HSA) was also investigated.