title: Sensitized photodecomposition of organic bisphosphonates by singlet oxygen.
abstract: During efforts to stabilize metal oxide bound chromophores for photoelectrochemical applications, a novel photochemical reaction has been discovered. In the reaction, the bisphosphonate functional groups -C(PO(3)H(2))(2)(OH) in the metal complex [Ru(bpy)(2)(4,4'-(C(OH)(PO(3)H(2))(2)bpy)](2+) are converted into -COOH and H(3)PO(4). The reaction occurs by sensitized formation of (1)O(2) by the lowest metal-to-ligand charge transfer excited state(s) of [Ru(bpy)(2)(4,4'-(C(PO(3)H(2))(2)(OH))(2)(bpy))](2+)* followed by (1)O(2) oxidation of the bisphosphonate substituent. A related reaction occurs for the bisphosphonate-based drug, risedronic acid, in the presence of O(2), light, and a singlet oxygen sensitizer ([Ru(bpy)(3)](2+) or Rose Bengal).
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hanson
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Ashford
authors.forename: Javier J
authors.initials: JJ
authors.lastname: Concepcion
authors.forename: Robert A
authors.initials: RA
authors.lastname: Binstead
authors.forename: Sohrab
authors.initials: S
authors.lastname: Habibi
authors.forename: Hanlin
authors.initials: H
authors.lastname: Luo
authors.forename: Christopher R K
authors.initials: CR
authors.lastname: Glasson
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Templeton
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Meyer
mesh_terms: D004164:Diphosphonates / Q000138:chemical synthesis / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D010756:Phosphoric Acids / Q000138:chemical synthesis / Q000737:chemistry; D055668:Photochemical Processes; D026082:Singlet Oxygen / Q000737:chemistry*
chemical_list: D004164:Diphosphonates; D009942:Organometallic Compounds; D010756:Phosphoric Acids; D026082:Singlet Oxygen