DNA groove-binding and acid-base properties of a Ru(II) complex containing anthryl moieties

DNA groove binders have been poorly studied as compared to the intercalators. A novel Ru(II) complex of [Ru(aeip)(2)(Haip)](PF6)(2) {Haip = 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline and aeip = 2-(anthracen-9-yl)-1-ethylimidazo[4,5-f][1, 10]phenanthroline} is synthesized and characterized by elemental analysis, H-1 NMR spectroscopy and mass spectrometry. The complex is evidenced to be a calf-thymus DNA groove binder with a large intrinsic binding constant of 10(6) M-1 order of magnitude as supported by UV-visible absorption spectral titrations, salt effects, DNA competitive binding with ethidium bromide, DNA melting experiment, DNA viscosity measurements and density functional theory calculations. The acid-base properties of the complex studied by UV-Vis spectrophotometric titrations are reported as well.