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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 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
    [(eta(6)-p-Pr(i)C6H4Me)(2)Ru2Mo2O6(OMe)(4)]: a new tetranuclear mixed-metal oxo cluster presenting a cube-based chair structure
    (1999)
    Plasseraud, Laurent
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    The title complex was obtained by reaction of [(eta(6)-p-Pr'C6H4Me)(4)Ru4Mo4O16] with methanol in the presence of p-hydroquinone. It contains an Mo2Ru2O2(OMe)(4) core consisting of two Mo2RuO(OMe)(3) half-cubes fused together to form a choir-like structure. (C) 1999 Elsevier Science S.A. All rights reserved.
  • Publication
    Métadonnées seulement
    Di-mu-bromo-bis[bromo(eta(6)-para-cymene)-ruthenium(II)] benzene solvate and di-mu-iodo-bis[(eta(6)-para-cymene)iodoruthenium(II)] toluene solvate
    (1999)
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    ;
    Plasseraud, Laurent
    ;
    Fidalgo, Eva Garcia
    ;
    Süss-Fink, Georg 
    The homologous title molecules, [Ru2Br4(C10H14)(2)]. C6H6, (1), and [Ru2I4(C10H14)(2)]. C7H8, (2), consist of arene-ruthenium moieties [Ru-to-ring distances of 1.655 (2) Angstrom in (1) and 1.673(3) Angstrom in (2)] with a terminal halogen ligand and [Ru-Br 2.548 (1) Angstrom in (1) and Ru-I 2.726(1) Angstrom in (2)], held together by two symmetrical halogen bridges [Ru-Br 2.575(1) Angstrom in (1) and Ru-I 2.736(1) Angstrom in (2)]. The arene rings are planar and parallel to each other, and the terminal halogen ligands are coordinated to rurthenium trans with respect to each other. Both molecules possess C-i symmetry.
  • Publication
    Métadonnées seulement
    Catalysis in aqueous solution: Hydrogenation of benzene derivatives catalysed by (eta(6)-C6H6)(2)Ru2Cl4
    (1998)
    Fidalgo, Eva Garcia
    ;
    Plasseraud, Laurent
    ;
    Süss-Fink, Georg 
    The catalytic hydrogenation of various benzene derivatives was studied, using (eta(6)-C6H6)(2)Ru2Cl4 in aqueous solution as the catalyst precursor. Under biphasic conditions, the corresponding cyclohexane derivatives are obtained with catalytic turnover rates which vary, depending on the substrate, from 20 to 2000 cycles per h. After a catalytic run, the aqueous solution contains the two tetranuclear cations [(eta(6)-C6H6)(4)RU4H4](2+) and [(eta(6)-C6H6)(4)Ru4H6](2+) which are known to catalyse the hydrogenation of aromatic compounds, but the activity of which is considerably lower than that of the (eta(6)-C6H6)(2)Ru2Cl4 precursor. An intermediate, presumably the more active species, was detected by H-1-NMR spectroscopy under catalytic conditions and identified as the trinuclear cluster cation [Ru-3(eta(6)-C6H6)(3)(mu(2)-Cl)(mu(3)-O)(mu(2)-H)(2)](+). (C) 1998 Elsevier Science B.V. All rights reserved.