Self-activated DNA cleavage of a water-soluble mononuclear Cu(II) complex with polyquinolinyl ligand

The synthesis and characterization of a water-soluble mononuclear Cu(II) complex, [CuLCl2]center dot 2CH(3)-CH2OH, where L = bis(2-quinolinyl methyl) benzyl-amine has been reported. L is a tridentate polyquinolinyl ligand, coordinated to Cu(II) via NNN donors. The central copper ion of 1 has N3Cl2 donor set in a distorted trigonal-bipyramidal geometry. The dimer existing in the solid state resulted from hydrogen bonds and pi-pi accumulation between two mononuclear units. The interaction of 1 with CT-DNA has been explored by absorption and emission titration methods, revealing partial intercalation between 1 and CT-DNA. Moreover, 1 could make pBR322 plasmid DNA cleaved by a self-activated oxidative process; hydroxyl radical and singlet oxygen may be the main reactive oxygen species species in the process. Complex 1 may quench the intrinsic fluorescence of bovine serum albumin in a static quenching process, which has been investigated by UV-visible and fluorescence spectroscopic methods. 1 also demonstrates potent cytotoxity against Hela cells with IC50 value of 2.84 mu M, which shows it to be a potential candidate as an anticancer metal-based drug.