title: Variation of DNA photocleavage efficiency for [(TL)2Ru(dpp)]Cl2 complexes where TL=2,2'-bipyridine, 1,10-phenanthroline, or 4,7-diphenyl-1,10-phenanthroline.
abstract: The complexes [(bpy)(2)Ru(dpp)]Cl(2), [(phen)(2)Ru(dpp)]Cl(2), and [(Ph(2)phen)(2)Ru(dpp)]Cl(2) (where dpp=2,3-bis(2-pyridyl)pyrazine, bpy=2,2'-bipyridine, phen=1,10-phenanthroline, Ph(2)phen=4,7-diphenyl-1,10-phenanthroline) have been investigated and found to photocleave DNA via an oxygen-mediated pathway. These light absorbing complexes possess intense metal-to-ligand charge transfer (MLCT) transitions in the visible region of the spectrum. The [(TL)(2)Ru(dpp)](2+) systems populate (3)MLCT states after visible light excitation, giving rise to emissions in aqueous solution centered at 692, 690, and 698nm for TL=bpy, phen, and Ph(2)phen respectively. The (3)MLCT states and emissions are quenched by O(2), producing a reactive oxygen species. These complexes photocleave DNA with varying efficiencies, [(Ph(2)phen)(2)Ru(dpp)](2+)>[(phen)(2)Ru(dpp)](2+)>[(bpy)(2)Ru(dpp)](2+). The presence of the polyazine bridging ligand will allow these chromophores to be incorporated into larger supramolecular assemblies.
authors.affiliation: Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0212, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Mongelli
authors.forename: Julie
authors.initials: J
authors.lastname: Heinecke
authors.forename: Shatara
authors.initials: S
authors.lastname: Mayfield
authors.forename: Benjamin
authors.initials: B
authors.lastname: Okyere
authors.forename: Brenda S J
authors.initials: BS
authors.lastname: Winkel
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Brewer
mesh_terms: D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D010777:Photochemistry
chemical_list: D009942:Organometallic Compounds; D010618:Phenanthrolines; C517177:Ruthenium (2,2'-bipyridine)-4,7-diphenyl-1,10-phenanthroline; C517176:Ruthenium(2,2'-bipyridine)-2,2'-bipyridine, 1,10-phenanthroline; D004247:DNA