Synthesis, solvatochromism, photochemistry, DNA binding, photocleavage, cytotoxicity and molecular docking studies of a ruthenium(II) complex bearing photoactive subunit.

A new pyrene-appended polypyridine ligand, wherein the 1,10-phenanthroline (phen) and the photoactive pyrene chromophore is connected via a C N bond; N-[1,10]phenanthrolin-5-yl-pyrenylmethanimine (ppym) and its complex [Ru(phen) 2 ( ppym ) ] 2+ was synthesized. Characterization of the ligand and the complex was investigated through elemental analysis, UV-vis, IR, 1 H NMR, MALDI-TOF mass and cyclic voltammetry techniques. The change in dipole moment of the ground and the excited state of the chromophores with the different solvent polarity was examined. The dual emission (Excimer) characteristics observed for ligand ppym has been probed by detailed photophysical studies involving variable concentration, excitation wavelength and solvent experiments and also transition metal ion induced quenching data. 3 MLCT emission was observed for [Ru(phen) 2 ( ppym ) ] 2+ . Absorption, emission, thermal melting and viscosity studies reveal that [Ru(phen) 2 ( ppym ) ] 2+ bind to CT DNA avidly and that ruthenium-bound ppym intercalate inside the base sets of the duplex. Also, the DNA photonicking activity (pBR 322 DNA, λ exc  = 450 nm) of [Ru(phen) 2 ( ppym ) ] 2+ is almost four times higher than [Ru(phen) 3 ] 2+ . Through inhibitor studies, we found that reactive oxygen species play a major role in the photo cleavage of [Ru(phen) 2 ( ppym ) ] 2+ . The cytotoxicity of the complex was tested in Human cancer cell line (ZR-75-30) by MTT assay. In addition, modeling studies scaffold the intercalative binding to the d(CGCAATTGCG) 2 sequence. [ABSTRACT FROM AUTHOR]