Luminescent pH sensing and DNA binding properties of a novel ruthenium(II) complex

A new Ru(II) complex, [Ru(bpy)(2)(dhipH(3))](ClO4)(2) (in which bpy - 2,2'-bipyridine, dhipH(3) = 3,4-dihydroxy-imidado[4,5-f][1,10]-phenanthroline), was synthesized and characterized, and the pH effect on the emission spectra of the complex was studied. The interaction of the complex with calf thymus DNA was investigated by UV-visible and emission spectroscopy, and viscosity measurements. The results suggest that the complex acted as a sensitive luminescent pH sensor and a strong ct-DNA intercalator with an intrinsic binding constant of (4.0 +/- 0.7) x 10(5) M-1 in buffered 50 mM NaCl. (C) 2004 Elsevier Inc. All rights reserved.