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Stoeckli-Evans, Helen

Nom
Stoeckli-Evans, Helen
Affiliation principale
Email
helen.stoeckli-evans@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/470

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  • 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
    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
    Accès libre
    Fixation and spontaneous dehydrogenation of methanol on a triruthenium–iridium framework: synthesis and structure of the cluster anion [HRu3Ir(CO)12(OMe)]–
    (1999)
    Süss-Fink, Georg 
    ;
    Plasseraud, Laurent
    ;
    Ferrand, Vincent
    ;
    Stoeckli-Evans, Helen 
    The anionic mixed-metal cluster [Ru3Ir(CO)13]–1, found to be catalytically active in the carbonylation of methanol, reacts with methanol at 70 °C to give, with O–H activation of the substrate, the cluster anion [HRu3Ir(CO)12(OMe)]–2, which upon prolonged reaction loses formaldehyde to give the cluster anion [H2Ru3Ir(CO)12]–3; both anions 2 and 3 crystallise together as the double-salt [N(PPh3)2]2[HRu3Ir(CO)12(OMe)][H2Ru3Ir(CO)12] the single-crystal X-ray structure analysis of which reveals a butterfly Ru3Ir skeleton for 2 and a tetrahedral Ru3Ir skeleton for 3.
  • Publication
    Métadonnées seulement
    Amphiphilic organoruthenium oxomolybdenum and oxovanadium clusters
    (1998)
    Süss-Fink, Georg 
    ;
    Plasseraud, Laurent
    ;
    Ferrand, Vincent
    ;
    Stanislas, Sandrine
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    ;
    Henry, Marc
    ;
    Laurenczy, Gábor
    ;
    Roulet, Raymond
    Para-cymene ruthenium dichloride dimer reacts in aqueous solution with sodium molybdate or sodium vanadate to give the amphiphilic clusters [(eta(6)-p-MeC(6)H(4)iPr)(4)Ru4Mo4O16] (1) and [(eta(6)-p-MeC(6)H(4)iPr)(4) Ru4V6O19] (4) respectively. The analogous reaction of hexamethylbenzene ruthenium dichloride dimer with sodium vanadate gives [(eta(6)-C6Me6)(4)Ru4V6O19] (5). The mixed-metal clusters [(eta(6)-p-MkC(6)H(4)iPr) Ru(eta(5)-C5Me5)(3)Rh3Mo4O16] (2) and [(eta(6)-p-MeC(6)H(4)iPr)(2)Ru-2(eta(5)-C5Me5)(2)Rh(2)Mo(4)O16] (3) are accessible from a mixture of para-cymene ruthenium dichloride dimer and pentamethylcyclopentadienyl rhodium dichloride dimer with sodium molybdate in aqueous solution. The crystal structure analyses of 1 and 3 reveal different framework geometries of the metal oxygen skeletons. O-17 NMR spectroscopy and partial charge calculations confirm the presence of three different types of oxygen atoms in 1. (C) 1998 Elsevier Science Ltd. All rights reserved.
  • Publication
    Accès libre
    [(p-PriC6H4Me)4 Ru4Mo4O16]: an amphiphilic organoruthenium oxomolybdenum cluster presenting a unique framework geometry
    (1997)
    Süss-Fink, Georg 
    ;
    Plasseraud, Laurent
    ;
    Ferrand, Vincent
    ;
    Stoeckli-Evans, Helen 
    The amphiphilic title compound, easily accessible from (p- cymene)ruthenium dichloride dimer and sodium molybdate in aqueous solution, presents an unprecedented Ru4Mo4O12 framework comprising a central Mo4O4 cube with four folded ORuO flaps resembling the sails of a windmill.