Vignette d'image

Süss-Fink, Georg

Nom
Süss-Fink, Georg
Affiliation principale
Fonction
Professeur ordinaire
Email
georg.suess-fink@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/385

Résultat de la recherche

Filtres

6
6
6
Réinitialiser les filtres

Paramètres

Voici les éléments 1 - 6 sur 6
  • Publication
    Métadonnées seulement
    Oxidation of 2-propanol and cyclohexane by the reagent "Hydrogen peroxide - Vanadate anion - Pyrazine-2-carboxylic acid": Kinetics and Mechanism
    (2007)
    Kozlov, Yuriy N
    ;
    Romakh, Vladimir B
    ;
    Kitaygorodskiy, Alex
    ;
    Buglyo, Peter
    ;
    Süss-Fink, Georg 
    ;
    Shul'pin, Georgiy B
    The 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.
  • Publication
    Métadonnées seulement
    Hydroperoxidation of methane and other alkanes with H2O2 catalyzed by a dinuclear iron complex and an amino acid
    (2002)
    Nizova, Galina V
    ;
    Krebs, Bernt
    ;
    Süss-Fink, Georg 
    ;
    Schindler, Siegfried
    ;
    Westerheide, Lars
    ;
    Gonzalez-Cuervo, Laura
    ;
    Shul'pin, Georgiy B
    The compound [Fe-2(HPTB)([mu-OH)(NO3)(2)](NO3)(2).CH3OH.2H(2)O (1) containing a dinuclear iron(III) complex in which HPTB=N,N,N',N'-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopro pane catalyzes the oxidation of alkanes with hydrogen peroxide in acetonitrile solution at room temperature only if certain amino acids (pyrazine-2-carboxylic, pyrazine-2,3-dicarboxylic or picolinic acid) are added to the reaction mixture. Alkyl hydroperoxides are formed as main reaction products. The turnover numbers attain 140 for cyclohexane, 21 for ethane and four for methane oxidation. The oxidation proceeds non-stereoselectively and bond selectivity parameters are low which testifies the participation of hydroxyl radicals in alkane functionalization. (C) 2002 Elsevier Science Ltd. All rights reserved.
  • Publication
    Métadonnées seulement
    Hydrogen peroxide oxidation of saturated hydrocarbons catalyzed by osmium compounds
    (2002)
    Shul'pin, Georgiy B
    ;
    Süss-Fink, Georg 
    Osmium derivatives, in particular OsCl3, catalyze the effective oxidation of saturated hydrocarbons in acetonitrile. The products formed are a ketone (aldehyde) and an alcohol. The addition of nitrogen heterocycles, such as pyridine, accelerated the reaction and increased the product yields. The ketone (aldehyde)/alcohol ratio dramatically changed in this case. In the presence of pyridine, the reaction occurred stereoselectively. The suggested reaction mechanism includes hydrogen atom abstraction from an alkane by an osmium oxo compound, resulting in the formation of the alkyl radical, which yields the alkylperoxyl radical after addition of an oxygen molecule. The latter radical degrades in the presence of the osmium complex under reaction conditions to give a ketone (aldehyde) and an alcohol.
  • Publication
    Métadonnées seulement
    Hydrogen hydroperoxide oxidation of ethane and other alkanes catalyzed by chromium compounds
    (2002)
    Süss-Fink, Georg 
    ;
    Shul'pin, Georgiy B
    Chromium oxo derivatives (H2CrO4) catalyze the effective oxidation of ethane and other saturated hydrocarbons with hydrogen peroxide or tert-butyl hydroperoxide in an acetonitrile solution at 60degreesC. Alkyl hydroperoxides, ketones (aldehydes), and alcohols are formed as main products. The oxidation of ethane gives ethyl hydroperoxide, acetaldehyde, ethanol, and acetic acid. The turnover frequency reaches 620 h(-1) in this case, and the product yield in terms of H2O2 consumed is 21%.
  • Publication
    Métadonnées seulement
    Alkane oxidation with hydrogen peroxide catalyzed homogeneously by vanadium-containing polyphosphomolybdates
    (2001)
    Süss-Fink, Georg 
    ;
    Gonzalez-Cuervo, Laura
    ;
    Shul'pin, Georgiy B
    Alkanes (cyclooctane, n-octane, adamantane, ethane) can be efficiently oxidized by hydrogen peroxide in acetonitrile using tetra-n-butylammonium salts of the vanadium-containing polyphosphomolybdates [PMo11 VO40](4-) and [PMo6V5O39](12-) as catalysts. The oxidation of alkanes gives rise to the corresponding alkyl hydroperoxides as the main products, which slowly decompose in the course of the reaction to produce the corresponding ketones (aldehydes) and alcohols. The reaction in acetic acid and water is much less efficient. The oxidation of cyclooctane at 60 degreesC in acetonitrile gives within 9 h oxygenates with turnover numbers > 1000 and yields > 30% based on the alkane. Pyrazine-2-carboxylic acid added as co-catalyst accelerates the reaction but does not enhance the product yield. The oxidation of the cis- and trans-isomers of decalin proceeds without retention of configuration. The mechanism assumed involves the reduction of V(V) to V(IV) by a first molecule of hydrogen peroxide, followed by the reaction of V(IV) with a second H2O2 Molecule to generate hydroxyl radicals. The latter abstract a hydrogen atom from the alkane, RH, leading to alkyl radicals, R-., which rapidly react with aerobic oxygen. The alkyl peroxy radicals thus formed are then converted into alkyl hydroperoxides. (C) 2001 Elsevier Science B.V. All rights reserved.
  • Publication
    Métadonnées seulement
    Oxidative functionalisation of ethane with hydrogen peroxide catalysed by chromic acid
    (2000)
    Shul'pin, Georgiy B
    ;
    Süss-Fink, Georg 
    ;
    Shul'pina, Lidia S
    Chromic acid catalyses efficiently (turnover numbers attain 620) the oxidation of alkanes including the very inert ethane by H2O2 or tert-BuOOH in acetonitrile solution at 60 degreesC; alkyl hydroperoxides, ketones (aldehydes) and alcohols are the main products.