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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
    Métadonnées seulement
    The kinetics and mechanism of cyclohexane oxygenation by hydrogen peroxide catalyzed by a binuclear iron complex
    (2003)
    Kozlov, Yuriy N
    ;
    Gonzalez-Cuervo, Laura
    ;
    Süss-Fink, Georg 
    ;
    Shul'pin, Georgiy B
    The binuclear iron complex containing 1,3,7-triazacyclononane and acetate bridges as ligands was found to catalyze effective oxidation of alkanes by hydrogen peroxide in acetonitrile at room temperature in the presence of pyrazine-2-carboxylic acid (P) as a cocatalyst. The primary reaction products were alkylhydroperoxides, which gradually decomposed to produce the corresponding ketones (aldehydes) and alcohols. Alkane activation was caused by the attack of hydroxyl radicals on a C-H alkane bond, which resulted in the formation of alkyl radicals. Hydroxyl radicals were generated in the rate-determining step of monomolecular decomposition of the iron diperoxo adduct with one P molecule. A kinetic model of the process that satisfactorily described the whole set of experimental data was suggested. The constants of supposed equilibria and the rate constant for the decomposition of the diperoxo complex of iron with P were estimated.
  • Publication
    Métadonnées seulement
    Mechanistic
    (2002)
    Laurenczy, Gábor
    ;
    Faure, Matthieu
    ;
    Vieille-Petit, Ludovic
    ;
    Süss-Fink, Georg 
    ;
    Ward, Thomas R
    In 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.
  • Publication
    Métadonnées seulement
    Cationic 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)
    Fidalgo, Eva Garcia
    ;
    Plasseraud, Laurent
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    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.
  • Publication
    Métadonnées seulement
    Reactivity 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)
    Süss-Fink, Georg 
    ;
    Fidalgo, Eva Garcia
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    The dinuclear hydride complex [(p-Me-C6H4-Pr')(2)Ru2Cl2(mu-Cl)(mu-H)] (1) reacts with the sodium halides NaX in methanol to give the halogen analogues [(p-Me-C6H4-Pr')(2)Ru2X2(mu-X)(mu-H)] (2: X = F, 3: X = Br, 4: X = I). With HX, complex 1 reacts to give the tetrahalo complexes [(p-Me-C6H4-Pr')(2)Ru2X2(mu-X)(2)] (5: X = Cl, 6: X = Br, 7: X = I); in the case of X = I, a large excess of HI leads to the formation of the cationic complex [(p-Me-C6H4-Pr')(2)Ru-2(mu-I)(3)](+) (8). The X-ray structure analysis of 1 shows a dinuclear Ru-2 backbone with two terminal chloro ligands being irans with respect to each other as the two p-cymene ligands, the two bridging ligands lie in a plane perpendicular to the plane defined by the terminal chloro ligands and the ruthenium atoms. (C) 2000 Elsevier Science S.A. All rights reserved.
  • Publication
    Métadonnées seulement
    The cluster dication [H6Ru4(C6H6)(4)](2+) revisited: the first cluster complex containing an intact dihydrogen ligand?
    (2000)
    Süss-Fink, Georg 
    ;
    Plasseraud, Laurent
    ;
    Maisse-Francois, Aline
    ;
    Stoeckli-Evans, Helen 
    ;
    Berke, Heinz
    ;
    Fox, Thomas
    ;
    Gautier, Régis
    ;
    Saillard, Jean-Yves
    A low-temperature H-1-NMR study suggests the tetranuclear cluster dication [H6Ru4(C6H6)(4)](2+) (1) to contain an H-2 ligand that undergoes, upon warming of the solution, an intramolecular exchange with the four hydride ligands at the Ru-4 framework. Whereas two of the three NMR signals at - 120 degrees C in the hydride region show T-1 values in the range 200-300 ms, the least deshielded resonance at delta = - 17.33 ppm exhibits a T-1 value of only 34 ms, characteristic of an H-2 ligand. a re-examination of the single-crystal X-ray structure analysis of the chloride salt of 1 supports this interpretation by a short distance of 1.14(0.15) Angstrom between two hydrogen atoms coordinated as a PI-PI ligand in a side-on fashion to one of the triangular faces of the Ru-4 tetrahedron. The distance between one of the two hydrogen atoms of the H-2 ligand and one of the four hydride ligands is also very short [1.33(0.15) Angstrom], suggesting an additional H-2... H interaction. The presence of this H-3, unit over one of the three Ru-3 faces in 1 may explain the deformation of the Ru-4 skeleton from the expected tetrahedral symmetry. Density functional theory (DFT) calculations on 1 indicate a very soft potential energy surface associated with the respective displacement of the three interacting cofacial hydrogen atoms. In accordance with these results, the cluster dication 1 tends to loose molecular hydrogen to form the cluster dication [H4Ru4(C6H6)(4)](2+) (2). The equilibrium between 1 and 2 can be used for catalytic hydrogenation reactions. (C) 2000 Elsevier Science S.A. All rights reserved.
  • Publication
    Métadonnées seulement
    Oxidations by the system "hydrogen peroxide manganese(IV) complex acetic acid" - Part II. Hydroperoxidation and hydroxylation of alkanes in acetonitrile
    (1999)
    Shul'pin, Georgiy B
    ;
    Süss-Fink, Georg 
    ;
    Smith, J R Lindsay
    Higher alkanes (cyclohexane, n-pentane, n-heptane, methylbutane, 2- and 3-methylpentanes, 3-methylhexane, cis- and trans-decalins) are oxidized at 20 degrees C by H2O2 in air in acetonitrile (or nitromethane) solution in the presence of the manganese(IV) salt [L2Mn2O3](PF6)(2) (L = 1,4,7-trimethyl-1,4-7-triazacyclononane) as the catalyst. An obligatory component of the reaction mixture is acetic add. Turnover numbers attain 3300 after 2 h, the yield of oxygenated products is 468 based on the alkane. The oxidation affords initially the corresponding alkyl hydroperoxide as the predominant product, however later these compounds decompose to produce the corresponding ketones and alcohols. Regio- and bond selectivities of the reaction are high: C(1) : C(2) : C(3) : C(4) approximate to 1 : 40 : 35 : 35 and 1 degrees : 2 degrees : 3 degrees is 1 : (15-40) : (180-300). The reaction with both. isomers of decalin gives (after treatment with PPh3) alcohols hydroxylated in the tertiary positions with the cis/trans ratio of similar to 2 in the case of cis-decalin, and of similar to 30 in the case of trans-decalin (i.e. in the latter case the reaction is stereospecific). Light alkanes (methane, ethane, propane, normal butane and isobutane) can be also easily oxidized by the same reagent in acetonitrile solution, the conditions being very mild: low pressure (1-7 bar of the alkane) and low temperature (-22 to +27 degrees C). Catalyst turnover numbers attain 3100, the yield of oxygenated products is 22% based on the alkane. The yields of oxygenates are higher at low temperatures. The ratio of products formed (hydroperoxide : ketone : alcohol) depends very strongly on the conditions of the reaction and especially on the catalyst concentration (at higher catalyst concentration the ketone is predominantly produced). (C) 1999 Elsevier Science Ltd. All rights reserved.