Mixed-ligand Cu(II) hydrazone complexes designed to enhance anticancer activity.

The ligand quantity, ligand type, and coordination geometry have important influences on the anticancer activity of metal-based complexes. On the basis of the structures of previously reported 1:1 Cu(II)/ligand complexes ([Cu(L1)Cl]·2HO 1a, [Cu(L2)Cl]·HO 2a, and [Cu(L2)NO]·HO 3a), we subsequently designed, developed, and characterized a series of corresponding 1:1:1 Cu(II)/ligand/co-ligand complexes ([Cu(L1)(Py)Cl]·HO 1b, [Cu(L2)(Py)Cl] 2b, and [Cu(L2)(Py)NO] 3b), where L1 = (E)-N'-(2-hydroxybenzylidene)acetohydrazide, L2 = (E)-N'-(2- hydroxybenzylidene)benzohydrazide, and Py = pyridine. All six Cu(II) complexes were assessed for their in vitro anticancer properties against a panel of human cancer cells, including cisplatin-resistant A549cisR cell lines.