title: Synthesis, DNA-binding and photocleavage studies of cobalt(III) mixed-polypyridyl complexes: [Co(phen)(2)(dpta)](3+) and [Co(phen)(2)(amtp)](3+).
abstract: Two novel cobalt(III) mixed-polypyridyl complexes [Co(phen)(2)(dpta)](3+) and [Co(phen)(2)(amtp)](3+) (phen=1,10-phenanthroline, dpta=dipyrido-[3,2-a;2',3'-c]- thien-[3,4-c]azine, amtp=3-amino-1,2,4-triazino[5,6-f]1,10-phenanthroline) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by spectroscopic, cyclic voltammetry, and viscosity measurements. Results suggest that the two complexes bind to DNA via an intercalative mode. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365nm. The mechanism studies reveal that hydroxyl radical (OH()) is likely to be the reactive species responsible for the cleavage of plasmid DNA by [Co(phen)(2)(dpta)](3+) and superoxide anion radical (O(2)(-)) acts as the key role in the cleavage reaction of plasmid DNA by [Co(phen)(2)(amtp)](3+).
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Peng
authors.forename: Hui
authors.initials: H
authors.lastname: Chao
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Liang-Nian
authors.initials: LN
authors.lastname: Ji
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D007364:Intercalating Agents / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010782:Photolysis; D010957:Plasmids / Q000737:chemistry* / Q000528:radiation effects; D013057:Spectrum Analysis; D013481:Superoxides / Q000737:chemistry; D014783:Viscosity
chemical_list: C520129:(3-amino-1,2,4-triazino(5,6-f)1,10-phenanthroline)bis(1,10-phenanthroline)cobalt(III); C520128:(dipyrido-(3,2-a-2',3'-c)thien(3,4-c)azine)bis(1,10-phenanthroline)cobalt(III); D007364:Intercalating Agents; D009942:Organometallic Compounds; D013481:Superoxides; D017665:Hydroxyl Radical; D004247:DNA; C427203:calf thymus DNA