title: A Synthetic Oxygen Atom Transfer Photocycle from a Diruthenium Oxyanion Complex.
abstract: Three new diruthenium oxyanion complexes have been prepared, crystallographically characterized, and screened for their potential to photochemically unmask a reactive Ru-Ru═O intermediate. The most promising candidate, Ru2(chp)4ONO2 (4, chp = 6-chloro-2-hydroxypyridinate), displays a set of signals centered around m/z = 733 amu in its MALDI-TOF mass spectrum, consistent with the formation of the [Ru2(chp)4O](+) ([6](+)) ion. These signals shift to 735 amu in 4*, which contains an (18)O-labeled nitrate. EPR spectroscopy and headspace GC-MS analysis indicate that NO2(•) is released upon photolysis of 4, also consistent with the formation of 6. Photolysis of 4 in CH2Cl2 at room temperature in the presence of excess PPh3 yields OPPh3 in 173% yield; control experiments implicate 6, NO2(•), and free NO3(-) as the active oxidants. Notably, Ru2(chp)4Cl (3) is recovered after photolysis. Since 3 is the direct precursor to 4, the results described herein constitute the first example of a synthetic cycle for oxygen atom transfer that makes use of light to generate a putative metal oxo intermediate.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Corcos
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: József S
authors.initials: JS
authors.lastname: Pap
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: Tzuhsiung
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: John F
authors.initials: JF
authors.lastname: Berry
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D008027:Light; D008670:Metals / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010782:Photolysis; D012428:Ruthenium / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D008670:Metals; D009589:Nitrogen Oxides; D012428:Ruthenium; D010100:Oxygen