title: A multifunctional tetrametallic Ru-Pt supramolecular complex exhibiting both DNA binding and photocleavage.
abstract: A new tetrametallic supramolecular complex, [{(bpy)2Ru(dpp)}2Ru(dpp)PtCl2](PF6)6 (bpy = 2,2'-bipyridine, dpp = 2,3-bis(2-pyridyl)pyrazine), has been prepared and characterized. This supramolecular assembly is multifunctional, forming coordinate covalent bonds to DNA through its cis-PtCl2 moiety and photocleaving DNA through its Ru polypyridine chromophores. Electronic absorption spectroscopy shows ligand-based pi-->pi* transitions in the UV with Ru-based metal-to-ligand charge transfer transitions throughout much of the visible. The Ru-->dpp CT transitions center at 542 nm (eta = 35 000 M-1 cm-1). This complex has a HOMO localized on peripheral Ru with E(1/2)oxd = 1.58 V vs Ag/AgCl, and a LUMO based on the mu-dpp connecting Ru and Pt, E(1/2)red = -0.40 V. Gel electrophoresis analysis shows the tetrametallic coordinates to pUC18 DNA and, when excited with visible light, cleaves DNA through an oxygen-mediated pathway.
authors.affiliation: Departments of Chemistry and Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0212, USA.
authors.forename: Ran
authors.initials: R
authors.lastname: Miao
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Mongelli
authors.forename: David F
authors.initials: DF
authors.lastname: Zigler
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* / Q000378:metabolism; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry*; D015394:Molecular Structure; D017671:Platinum Compounds / Q000737:chemistry*; D012413:Rubidium / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; D017671:Platinum Compounds; D004247:DNA; D012413:Rubidium