- Selective catalytic 2e--oxidation of organic substrates by an FeIIcomplex having an N-heterocyclic carbene ligand in water
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An FeII complex, 1, having a pentadentate ligand with an NHC moiety catalyzes substrate oxidation to afford 2e-oxidized products with high selectivity by suppression of overoxidation in water. A Bell-Evance-Polanyi plot for the substrate oxidation catalyzed by 1 exhibited an inflection point around 86 kcal mol-1, indicating strong C-H abstraction ability of the reactive species derived from 1.
- Fujisaki, Hiroto,Ishizuka, Tomoya,Shimoyama, Yoshihiro,Kotani, Hiroaki,Shiota, Yoshihito,Yoshizawa, Kazunari,Kojima, Takahiko
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- Photocatalytic oxidation of organic compounds in water by using ruthenium(II)-pyridylamine complexes as catalysts with high efficiency and selectivity
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The photocatalytic oxidation of organic substrates such as alcohols was conducted in the presence of RuII-aqua complexes as oxidation catalysts, [RuII(bpy)3]2+ as a photosensitizer and electron mediator, and a CoIII complex as a sacrificial oxidant (see scheme). The catalytic systems exhibited high efficiency to achieve turnover numbers of over 8000. Copyright
- Ohzu, Shingo,Ishizuka, Tomoya,Hirai, Yuichirou,Fukuzumi, Shunichi,Kojima, Takahiko
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- Hydrogen production coupled to hydrocarbon oxygenation from photocatalytic water splitting
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On the sunny side: A homogeneous system for H2 production and hydrocarbon oxidation was developed in the absence of any sacrificial reagent. This system consists of [Ru(TPA)(H2O)2]2+ and [Fe3(CO)12] as catalysts and [Ru(bpy)3] 2+ and [Ir(bpy)(ppy)2]+ as photosensitizers (PS). Water is the oxygen source as well as the source for H2 formation (see picture; Sub=organic substrate). Copyright
- Singh, Wangkheimayum Marjit,Pegram, Derek,Duan, Haifeng,Kalita, Diganta,Simone, Paul,Emmert, Gary L.,Zhao, Xuan
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- Visible-Light-Driven Oxidation of Organic Substrates with Dioxygen Mediated by a [Ru(bpy)3]2+/Laccase System
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Oxidation reactions are highly important chemical transformations that still require harsh reaction conditions and stoichiometric amounts of chemical oxidants that are often toxic. To circumvent these issues, olefins oxidation is achieved in mild conditions upon irradiation of an aqueous solution of the complex [Ru(bpy)3]2+ and the enzyme laccase. Epoxide formation is coupled to the light-driven reduction of O2 by [Ru(bpy)3]2+/laccase system. The reactivity can be explained by dioxygen acting both as an oxidative agent and as renewable electron acceptor, avoiding the use of a sacrificial electron acceptor.
- Schneider, Ludovic,Mekmouche, Yasmina,Rousselot-Pailley, Pierre,Simaan, A. Jalila,Robert, Viviane,Réglier, Marius,Aukauloo, Ally,Tron, Thierry
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- A Reversible Electron Relay to Exclude Sacrificial Electron Donors in the Photocatalytic Oxygen Atom Transfer Reaction with O2 in Water
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Using light energy and O2 for the direct chemical oxidation of organic substrates is a major challenge. A limitation is the use of sacrificial electron donors to activate O2 by reductive quenching of the photosensitizer, generating undesirable side products. A reversible electron acceptor, methyl viologen, can act as electron shuttle to oxidatively quench the photosensitizer, [Ru(bpy)3]2+, generating the highly oxidized chromophore and the powerful reductant methyl-viologen radical MV+.. MV+. can then reduce an iron(III) catalyst to the iron(II) form and concomitantly O2 to O2.? in an aqueous medium to generate an active iron(III)-(hydro)peroxo species. The oxidized photosensitizer is reset to its ground state by oxidizing an alkene substrate to an alkenyl radical cation. Closing the loop, the reaction of the iron reactive intermediate with the substrate or its radical cation leads to the formation of two oxygenated compounds, the diol and the aldehyde following two different pathways.
- Vo, Nhat Tam,Mekmouche, Yasmina,Tron, Thierry,Guillot, Régis,Banse, Frédéric,Halime, Zakaria,Sircoglou, Marie,Leibl, Winfried,Aukauloo, Ally
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- Chemical and photochemical oxidation of organic substrates by ruthenium aqua complexes with water as an oxygen source
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Two ruthenium aqua complexes were shown to be effective catalysts in chemical and photochemical oxidation of hydrocarbons. A remarkable activity (up to 90% yield and 100% selectivity) was performed in conversion of sulfide to sulfoxide by homogeneous photooxidation.
- Li, Fei,Yu, Miao,Jiang, Yi,Huang, Fang,Li, Yanqing,Zhang, Biaobiao,Sun, Licheng
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supporting information; experimental part
p. 8949 - 8951
(2011/10/02)
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