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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

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  • Publication
    Accès libre
    Conception de matériaux dendritiques chiraux mésomorphes pour l’élaboration de commutateurs électroactifs basés sur le couple ferrocène/ferrocenium
    (2010)
    Kopp, Cyril
    ;
    Deschenaux, Robert 
    ;
    Süss-Fink, Georg 
    Ce travail de thèse traite de la conception de nouveaux matériaux mésomorphes. Deux dendrimères chiraux ont été synthétisés dans le but de transmettre leurs propriétés liquides-cristallines à un dérivé du ferrocène. Une évolution vers les ferrocènes peralkylés a permis d‟obtenir des ferrocéniums stables montrant une modification (commutation) des propriétés mésomorphes. Puis, grâce à une variation dans la construction du cœur dendritique, nous avons mis en évidence de manière distincte le rôle du dendrimère ainsi que de l‟oxydation. Ces mêmes dendrimères ont également trouvé d‟autres utilisations. Les fonctions se trouvant au cœur du dendrimère ont été modulées par des réactions d‟estérification avec différentes petites chaînes. Dès lors, ces nouveaux composés ont été utilisés dans la conception de composés de « type Janus » ayant comme partie centrale soit un malonate soit un cycle triazole. Ces composés ont montré d‟intéressantes propriétés liquides-cristallines., This thesis focuses on the design of new mesomorphic materials. Two chiral dendrimers were synthesized with the aim to transfer their liquid-crystalline properties to ferrocene derivatives. An evolution towards peralkylated ferrocene gave stable ferrocenium derivatives showing a switch between liquid-crystalline phases. The role of the dendritic structure and oxidation could be explained. Then, the functions located at the focal point of the dendrimers were modulated by esterification reactions. Therefore, these new compounds were used in the design of “Janus type” compounds having as central units a malonate or a triazol ring. These compounds showed interesting liquid-crystalline properties.
  • Publication
    Accès libre
    Dinuclear iron, ruthenium and cobalt complexes containing 1,4-dimethyl-1,4,7-triazacyclononane ligands as well as carboxylato and oxo or hydroxo bridges
    (2006)
    Romakh, Vladimir B.
    ;
    Therrien, Bruno 
    ;
    Labat, Gael
    ;
    Stoeckli-Evans, Helen 
    ;
    Shul’pin, Georgiy B.
    ;
    Süss-Fink, Georg 
    The reaction of 1,4-dimethyl-1,4,7-triazacyclononane (L–Me2) with FeSO4 • 7H2O in aqueous ethanol gives, in the presence of sodium carboxylates, hydrogen peroxide, sodium hydroxide and KPF6, the dinuclear Fe(III)–Fe(III) complex cations [(L–Me2)2Fe2(O)(OOCR) 2]2+ (R = H: 1, R = CH3: 2, R = C6H5: 3), which crystallise as the hexafluorophosphate salts. The corresponding reaction with RuCl3 • nH2O does not work, however, the analogous Ru(III)–Ru(III) complex [(L–Me2)2Ru2 (O)(OOCCH3)2]2+ (5) can be synthesised by reacting Ru(dmso)4Cl2 with L–Me2, HCl and air in refluxing ethanol, followed by addition of sodium acetate, the mononuclear intermediate (L–Me2)RuCl3 • H2O (4) being also isolated and characterised. The reaction of L–Me2, sodium acetate, hydrogen peroxide and triethylamine with CoCl2 • 6H2O in acetonitrile yields, however, the hydroxo-bridged Co(III)–Co(III) complex [(L–Me2)2Co2 (OH)(OOCCH3)2]3+ (6). The molecular structures of 2, 5 and 6, solved by single-crystal X-ray structure analyses of the hexafluorophosphate salts, reveal for the orange crystals of [2][PF6]2 a Fe–Fe distance of 3.104(1) Å, for the purple crystals of [5][PF6]2 a Ru–Ru distance of 3.230(1) Å, and for the violet crystals of [6][PF6]3 • (CH3)2CO a Co–Co distance of 3.358(1) Å. All six complexes show catalytic activity for the oxidation of isopropanol with hydrogen peroxide in water to give acetone in the presence of ascorbic acid as co-catalyst.
  • Publication
    Accès libre
    Hydrogen Peroxide Oxygenation of Alkanes Including Methane and Ethane Catalyzed by Iron Complexes in Acetonitrile
    (2004)
    Shulpin, Georgiy B.
    ;
    Nizova, Galina V.
    ;
    Kozlov, Yuriy N.
    ;
    Gonzalez Cuervo, Laura
    ;
    Süss-Fink, Georg 
    This paper describes an investigation of the alkane oxidation with hydrogen peroxide in acetonitrile catalyzed by iron(III) perchlorate (1), iron(III) chloride (2), iron(III) acetate (3) and a binuclear iron(III) complex with 1,4,7-triazacyclononane (4). The corresponding alkyl hydroperoxides are the main products. Nevertheless in the kinetic study of cyclohexane oxidation, the concentrations of oxygenates (cyclohexanone and cyclohexanol) were measured after reduction of the reaction solution with triphenylphosphine (which converts the cyclohexyl hydroperoxide to the cyclohexanol). Methane and ethane can be also oxidized with TONs up to 30 and 70, respectively. Chloride anions added to the oxidation solution with 1 activate the perchlorate iron derivative in acetonitrile, whereas the water as additive inactivates 2 in the H2O2 decomposition process. Pyrazine-2-carboxylic acid (PCA) added to the reaction mixture decreases the oxidation rate if 1 or 2 are used as catalysts, whereas compounds 3 and 4 are active as catalysts only in the presence of small amount of PCA. The investigation of kinetics and selectivities of the oxidations demonstrated that the mechanisms of the reactions are different. Thus, in the oxidations catalyzed by the 1, 3+PCA and 4+PCA systems the main oxidizing species is hydroxyl radical, and the oxidation in the presence of 2 as a catalyst has been assumed to proceed (partially) with the formation of ferryl ion, (FeIV=O)2+. In the oxidation catalyzed by the 4+PCA system (TONs attain 240) hydroxyl radicals were generated in the rate-determining step of monomolecular decomposition of the iron diperoxo adduct containing one PCA molecule. A kinetic model of the process which satisfactorily describes the whole set of experimental data was suggested. The constants of supposed equilibriums and the rate constant for the decomposition of the iron diperoxo adduct with PCA were estimated.
  • Publication
    Accès libre
    Catalytic functionalization of methane
    (2000)
    Süss-Fink, Georg 
    ;
    Stanislas, Sandrine
    ;
    Shulpin, Georgiy B.
    ;
    Nizova, Galina V.
    A mixture of sodium vanadate and pyrazine-2-carboxylic acid (pcaH) efficiently catalyses the reaction of methane with molecular oxygen (from air) and hydrogen peroxide to give methyl hydroperoxide and, as consecutive products, methanol and formaldehyde. The reaction takes place under mild conditions (25-75 °C) either in aqueous or in acetonitrile solution. The complexes formed from the catalyst precursor and the co-catalyst (under the reaction conditions) have been isolated and characterized as the derivatives [VO2(pca)2]- (1) and [VO(O2) (pca)2]- (3). The implications of these species in the catalytic process are discussed.