Voici les éléments 1 - 2 sur 2
  • Publication
    Métadonnées seulement
    New iso and heteropolyoxomolybdates: synthesis and molecular structure of the anions [(Mo8O26)-O-VI(OH)](5-), [(HAsAsMoMo8O34)-As-III-Mo-V-Mo-V-O-VI](6-) and [(HAsAsMoMo8O34)-As-III-Mo-V-Mo-V-O-VI{Co(C5H5N)(2)(H2O)(3)}](4-)
    (2002)
    Fidalgo, Eva Garcia
    ;
    Neels, Antonia
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    ;
    The hydrothermal reaction of Na2MoO4 with pyridine in water at pH 5 and 130 degreesC gives the octamolybdate anion [Mo-8(VI) O-26(OH)](5-) (1) which crystallises as the pyridinium salt; its molecular structure derives from that of the parent alpha-octamolybdate anion [Mo-8(VI) O-26](4-) by opening two molybdenum-oxygen bond and adding a hydroxo bridge. The same reaction in the presence of NaAsO2 yields the mixed-valence arsenatomolybdate [Has(III)As(V)Mo(V)Mo(8)(VI)O(34)](6-) (2) which is also isolated as the pyridinium salt. Anion 2 has a lacunary structure like an open basket, which derives from the famous alpha-Keggin structure by removing three edge-sharing MoO6 octahedra and by capping a trioxygen face of three remaning MoO6 octahedra with an AsH group. Reaction of 2 with Co2+ leads to the anion [(HAsAsMoMo8VI)-As-III-Mo-V-Mo-V O-34 {Co(C5H5N)(2)(H2O)(3)}](4-) (3) which crystallises as a double pyridinium salt together with anion 2. The structure of 3 derives from that of 2 by attaching a Co(C5H5N)(2)(H2O)(3) fragment to a terminal oxo ligand. Reaction of 2 with hydrogen peroxide produces the fully oxydised alpha-Keggin anion [(AsMo12O40)-Mo-V-O-VI](3-) (4) which was found to crystallise as the tetrabutylammonium salt surprisingly with three independent molecules in the unit cell, two of them showing a remarkable disorder. (C) 2002 Elsevier Science Ltd. 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
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    ;
    Plasseraud, Laurent
    ;
    Fidalgo, Eva Garcia
    ;
    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.