Synthesis and Structure of a Cytotoxic Complex of Copper(II) with Phenanthroline and Benzimidazole Derivatives

The [Cu(phendione)LBr₂]·C₂H₅OH complex (1) is prepared by the interaction of copper(II) bromide with 1,10-phenanthroline-5,6-dione (phendione) and 1-(1H-benzamidazole-1-ylmethyl)-1H-1,2,3-benzotriazole (L). The compound is characterized by elemental analysis, powder XRD, and IR spectroscopy. It is shown by single crystal XRD that the complex is mononuclear, and the environment of its central atom is formed by two bromide anions, three nitrogen atoms of the 1,10-phenanthroline-5,6-dione chelating ligand, and the L ligand coordinated in a monodentate mode by a nitrogen atom of the benzimidazole ring. The stability of 1 in an ethanol/DMSO mixture and in a phosphate-buffered saline for 48 h is studied. The cytotoxicity of the ligands and the copper(II) complex is studied on the lung adenocarcinoma cell line (A549) and non-tumor human lung fibroblasts (MRC5). It is shown that the complex exhibits cytotoxic activity on both cell lines and exerts selective action against A549 cells.