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Süss-Fink, Georg
Nom
Süss-Fink, Georg
Affiliation principale
Fonction
Professeur ordinaire
Email
georg.suess-fink@unine.ch
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Résultat de la recherche
Voici les éléments 1 - 9 sur 9
- PublicationMétadonnées seulementOxidation of 2-propanol and cyclohexane by the reagent "Hydrogen peroxide - Vanadate anion - Pyrazine-2-carboxylic acid": Kinetics and Mechanism(2007)
; Shul'pin, Georgiy BThe vanadate anion in the presence of pyrazine-2-carboxylic acid (PCA equivalent to pcaH) efficiently catalyzes the oxidation of 2-propanol by hydrogen peroxide to give acetone. UV-vis spectroscopic monitoring of the reaction as well as the kinetics lead to the conclusion that the crucial step of the process is the monomolecular decomposition of a diperoxovanadium(V) complex containing the pca ligand to afford the peroxyl radical, HOO center dot and a V(IV) derivative. The rate-limiting step in the overall process may not be this (rapid) decomposition itself but (prior to this step) the slow hydrogen transfer from a coordinated H2O2 molecule to the oxygen atom of a pca ligand at the vanadium center: "(pca)(O)V center dot center dot center dot O2H2" -> "(pca)(HO-)V-OOH". The V(IV) derivative reacts with a new hydrogen peroxide molecule to generate the hydroxyl radical ("V-IV" + H2O2 -> "V-V" + HO- + HO center dot), active in the activation of isopropanol: HO center dot + Me2CH(OH) -> H2O + Me2C center dot(OH). The reaction with an alkane, RH, in acetonitrile proceeds analogously, and in this case the hydroxyl radical abstracts a hydrogen atom from the alkane: HO center dot + RH -> H2O + R-center dot. These conclusions are in a good agreement with the results obtained by Bell and co-workers (Khaliullin, R. Z.; Bell, A. T.; Head-Gordon, M. J. Phys. Chem. B 2005, 109, 17984-17992) who recently carried out a density functional theory study of the mechanism of radical generation in the reagent under discussion in acetonitrile. - PublicationMétadonnées seulementElectron deficiency in tetrahedral transition-metal clusters: Electronic structure and magnetic properties of [Ru-4(eta(6)-C6H6)(4)(mu(3)-H)(4)](2+)(2003)
; Saillard, Jean-YvesAnalysis of the electronic structure of the electron-deficient cluster cation [Ru-4(eta(6)-C6H6)(4)H-4](2+) (1(2+)) by density functional theory calculations shows a very small energy gap (0.06 eV) between the diamagnetic singlet state and the paramagnetic triplet state, as a consequence of the absence of a significant Jahn-Teller distortion in the molecular structure of 1(2+). Magnetic measurements of [1]Cl-2, [1][BF4](2), and [1][PF6](2) show 1(2+) to be diamagnetic in the fundamental state, with some weak temperature-independent paramagnetism, depending upon the nature of the counterion. - PublicationMétadonnées seulementMechanistic(2002)
; Ward, Thomas RIn situ high-pressure NMR spectroscopy of the hydrogenation of benzene to give cyclohexane, catalysed by the cluster cation [(eta(6)-C6H6) (eta(6)-C6Me6)(2)Ru-3(mu(3)-O)(mu(2)-OH)(mu(2)-H)(2)](+) 2, supports a mechanism involving a supramolecular host-guest complex of the substrate molecule in the hydrophobic pocket of the intact cluster molecule. - PublicationMétadonnées seulementSupramolecular cluster catalysis: Benzene hydrogenation catalyzed by a cationic triruthenium cluster under biphasic conditions(2002)
; - PublicationMétadonnées seulementThe cluster dication [(eta(6)-C6H6)(2)(eta(6)-C6Me6)(4)Ru-8(mu(2)-H)(2)(mu(3)-O)(2)(mu(2)-Cl) (2)](2+): a chloro-bridged framework containing two metal tetrahedra(2002)
; The title complex was obtained by reacting [(eta(6)-C6H6)(eta(6)-C6Me6)(2)Ru-3(mu(2)-H)(3)(mu(3)-O)(+) with RuCl3 . nH(2)O in aqueous solution. it crystallises as the tetrafluoroborate salt. The cationic cluster is formed of two tetrahedral Ru-4 substructures which are held together by two chloro bridges. (C) 2002 Elsevier Science B.V. All rights reserved. - PublicationMétadonnées seulementOxidations by the system "hydrogen peroxide-manganese(IV) complex-carboxylic acid" Part 3. Oxygenation of ethane, higher alkanes, alcohols, olefins and sulfides(2001)
; Shul'pina, Lidia SThe manganese(IV) complex salt [L2Mn2O3](PF6)(2) (L = 1,4,7-trimethyl-1,4,7-triazacyclononane) (compound 1, see Scheme 1) very efficiently catalyzes the hydroperoxidation of saturated hydrocarbons, including ethane by H2O2 in acetontitrile or nitromethane solution at low (room or lower) temperature, provided a carboxylic (typically acetic) acid is present. The hydroperoxidation of tertiary positions in disubstituted cyclohexanes proceeds with partial retention of configuration in nitromethane or acetonitrile solution, while the stereoselectivity of the reaction is only negligible in acetone solution. The system "H2O2-compound 1-MeCO2H" also transforms secondary alcohols into the corresponding ketones with quantitative yields at room temperature within a few minutes; the yields of aldehydes and carboxylic acids in the oxidation of primary alcohols are lower. Terminal aliphatic olefins such as hexene-1 are quantitatively epoxidized by the same system in acetonitrile at room temperature within 20 min, while the epoxide yield in the analogous reaction with styrene attains only 60% under the same conditions. Finally, dimethylsulfide can be quantitatively and selectively converted into dimethylsulfoxide within 3h at room temperature. The system "tert-BuOOH-compound 1" also oxidizes alkanes, addition of acetic acids has less pronounced effect on the direction and efficiency of the reaction, Two other checked derivative of Mn(IV) (compounds 2 and 3) as well a porphyrin complex of Mn(III) (compound 4) exhibited lower activity in catalysis of alkane oxidation with tert-BuOOH. (C) 2001 Elsevier Science B.V. All rights reserved. - PublicationMétadonnées seulementCationic dinuclear arene ruthenium complexes with one hydroxo and two chloro bridges: synthesis and molecular structure of [(p-Me-C6H4 Pr-i)(2)Ru-2(mu-Cl)(2)(mu-OH)][ReO4](2001)
; The dinuclear complexes (arene)(2)Ru2Cl4 (arene = benzene, p-cymene, durene, hexamethylbenzene) react in aqueous solution to give, in addition to the known cationic trichloro complexes [(arene)(2)Ru-2(mu -Cl)(3)](+), the new dichloro hydroxo cations [(arene)(2)Ru-2(mu -Cl)(2)(mu -OH)](+) which can be isolated as the perrhenate salts. (C) 2001 Published by Elsevier Science B.V. - PublicationMétadonnées seulementReactivity of dinuclear arene ruthenium complexes: reactions of the hydrido complex [(p-Me-C6H4-Pr-i)(2)Ru2Cl2(mu-Cl)(mu-H)] with NaX and HX (X = F, Cl, Br, I)(2000)
; - PublicationMétadonnées seulementThe cluster dication [H6Ru4(C6H6)(4)](2+) revisited: the first cluster complex containing an intact dihydrogen ligand?(2000)
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