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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]

6-azauridine (AzU), a pyrimidine nucleoside antimetabolite, was known to inhibit the growth of microorganism and transplantable tumors. The binding affinity of AzU to blood serum proteins might influence the effectiveness of the drug. Herein, we investigated the interaction of AzU with bovine serum albumin (BSA) under near physiological conditions. Fluorescence spectroscopy analysis revealed that AzU strongly quenched the intrinsic fluorescence of BSA through a static quenching procedure, and a non-radiation energy transfer occurred within the molecules. Thermodynamic parameter determined from the temperature dependent binding constant suggests that the interaction of AzU with BSA is governed by enthalpic forces with a negative entropic contribution. Displacement studies and protein/drug docking studies suggest that AzU binds non-competitively to both sub-domain IIA and sub-domain IIIA of BSA. The obtained results reveal that AzU can bind to BSA with considerable affinity even in the presence of coexisting drug and can be used along with other drugs. [ABSTRACT FROM AUTHOR]