title: DNA-binding studies of mixed-ligand (ethylenediamine)ruthenium(II) complexes.
abstract: A series of mixed-ligand ruthenium(II) complexes of the type [Ru(en)(2)bpy](2+) (bpy=2,2-bipyridine; 1), [Ru(en)(2)phen](2+) (phen=1,10-phenantroline; 2), [Ru(en)(2)IP](2+) (IP=imidazo[4,5-f][1,10]phenanthroline; 3), and [Ru(en)(2)PIP](2+) (PIP=2-phenylimidazo[4,5-f][1,10]phenanthroline; 4) have been isolated and characterized by UV/VIS, IR, and (1)H-NMR spectral methods. The binding of the complexes with calf thymus DNA has been investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photo-cleavage. The spectroscopic studies together with viscosity measurements and DNA melting studies support that complexes 1 and 2 bind to CT DNA (=calf thymus DNA) by groove mode. Complex 2 binds more avidly to CT DNA than complex 1, complexes 3 and 4 bind to CT DNA by intercalation mode, 4 binds more avidly to CT DNA than 3. Noticeably, the four complexes have been found to be efficient photosensitisers for strand scissions in plasmid DNA.
authors.affiliation: Department of Chemistry, Osmania University, 500007 Hyderabad, Andhra Pradesh, India.
authors.forename: Penumaka
authors.initials: P
authors.lastname: Nagababu
authors.forename: J Naveena Lavanya
authors.initials: JN
authors.lastname: Latha
authors.forename: Sirasani
authors.initials: S
authors.lastname: Satyanarayana
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002621:Chemistry / Q000379:methods; D004247:DNA / Q000737:chemistry*; D005029:Ethylenediamines / Q000737:chemistry*; D007477:Ions; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D009690:Nucleic Acid Conformation; D017319:Photosensitizing Agents / Q000494:pharmacology; D012428:Ruthenium / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013950:Thymus Gland / Q000737:chemistry
chemical_list: D005029:Ethylenediamines; D007477:Ions; D008024:Ligands; D017319:Photosensitizing Agents; C031234:ethylenediamine; D012428:Ruthenium; D004247:DNA