title: DNA-binding and photocleavage studies of cobalt(III) mixed-polypyridyl complexes containing 2-(2-chloro-5-nitrophenyl)imidazo [4,5-f][1,10]phenanthroline.
abstract: The ligand 2-(2-chloro-5-nitrophenyl)imidazo[4,5-f][1,10]phenanthroline(CNOIP) and its complexes [Co(bpy)(2)(CNOIP)](3+) (1) and [Co(phen)(2)(CNOIP)](3+) (2) (bpy=2,2'-bipyridine; phen=1,10-phenanthroline) have been synthesized and characterized. Binding of the two complexes with calf thymus DNA has been investigated by spectroscopic methods, cyclic voltammetry, viscosity, and electrophoresis measurements. The experimental results indicate that both complexes bind to DNA through an intercalative mode. In comparison with their parent complexes containing PIP ligand (PIP=2-phenylimidazo[4,5-f][1,10]phenanthroline), the introduction of NO(2) and Cl groups to the PIP ligand decreased the binding affinity of complexes 1 and 2 to CT DNA. Both complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA, the hydroxyl radical (OH*) is suggested to be the reactive species responsible for the cleavage.
authors.affiliation: The Key Laboratory of Gene Engineering of Ministry of Education and Department of Chemistry, Zhongshan University, Guangzhou 510275, PR China.
authors.forename: Q L
authors.initials: QL
authors.lastname: Zhang
authors.forename: J G
authors.initials: JG
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: G Q
authors.initials: GQ
authors.lastname: Xue
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: J Z
authors.initials: JZ
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Zhou
authors.forename: L H
authors.initials: LH
authors.lastname: Qu
authors.forename: L N
authors.initials: LN
authors.lastname: Ji
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D004247:DNA / Q000378:metabolism*; D006868:Hydrolysis; D007093:Imidazoles / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D010618:Phenanthrolines / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D010777:Photochemistry; D010957:Plasmids; D011725:Pyridines / Q000737:chemistry*; D014783:Viscosity
chemical_list: C437424:2-(2-chloro-5-nitrophenyl)imidazo(4,5-f)(1,10)phenanthroline; D007093:Imidazoles; D010618:Phenanthrolines; D011725:Pyridines; D003035:Cobalt; D004247:DNA