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Stoeckli-Evans, Helen
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Stoeckli-Evans, Helen
Affiliation principale
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helen.stoeckli-evans@unine.ch
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Voici les éléments 1 - 10 sur 29
- PublicationMétadonnées seulementConversion of ethylene into ethylidyne on a mixed-metal cluster: synthesis and structure of IrRu4(CO)(15)(mu(4)-CH3)(1999)
; The thermal reaction of the tetranuclear cluster HIrRu3(CO)(13) with ethylene in hexane (90 degrees C, 2 bar) affords, in addition to H3IrRu3(CO)(12), the pentanuclear cluster HIrRu4(CO)(15)(mu(4)-C-CH3) (1) in which the ethylidyne ligand is coordinated through a carbon atom to the four ruthenium atoms in the IrRu4 core. In this reaction, the CH2=CH2 molecule has been transformed into a C-CH3 moiety coordinated as a mu(4)-ligand to the cluster. (C) 1999 Elsevier Science S.A. All rights reserved. - PublicationMétadonnées seulementMetal-framework degradation reactions of the mixed-metal cluster anions [M3Ir(CO)(13)](-) (M=Ru, Os) with bis(diphenylphosphino)methane and with tricyclohexylphosphine: synthesis and structure of HRu2Ir(CO)(5)(dppm)(3), HRu2Ir(CO)(6)(PCy3)(3), H2Os2Ir2(CO)(10)(PCy3)(2) and H3Os3Ir(CO)(8)(PCy3)(3)(1999)
; - PublicationMétadonnées seulementNew Ru-3(CO)(12) derivatives with bulky diphosphine ligands: synthesis, structure and catalytic potential for olefin hydroformylation(2001)
; The diphosphine clusters Ru-3(CO)(10)(dcpm) (1) and Ru-3(CO)(10)(F-dppe) (2) as well as the bis(diphosphine) clusters Ru-3(CO)(8)(dcpm)(2) (3) and Ru-3(CO)(8)(F-dppe)(2) (4) have been synthesised from Ru-3(CO)(12) and the bulky diphosphines 1,2-bis[bis(pentafluorophenyl)phosphino]ethane (F-dppe) and bis(dicyclohexylphosphino)methane (dcpm). While the single-crystal X-ray structure analyses of 1, 2 and 3 show the expected mu (2)-eta (2) coordination of the diphosphine ligands, that of 4 reveals an unusual structure with one mu (2)-eta (2)-diphosphine and one mu (1)-eta (2)-diphosphine ligand. The clusters 1-4 catalyse the hydroformylation of ethylene and propylene to give the corresponding aldehydes, 2 showing higher activities than those observed for Ru-3(CO)(12) and Ru-3(CO)(10)(dppc). (C) 2001 Elsevier Science Ltd. All rights reserved. - PublicationMétadonnées seulementReactions of the cluster anion [HRu3(CO)(11))](-) with dicyclohexylphosphine: Synthesis and molecular structure of H2Ru3(CO)(8)(PCy2)(2) and H2Ru3(CO)(6)(PCy2)(2)(HPCy2)(2)(2001)
; - PublicationMétadonnées seulementReactions of the cationic complex [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(3)](+) with nitrogen-containing heterocycles in aqueous solution(1998)
; The dinuclear cation [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(3)](+) (1) reacts in aqueous solution with pyrazole and 4-methylpyrazole to give the bispyrazolato complexes [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-N2C3H2R)(2)](+) (R = H: 2, R = Me: 3). The reaction with 1,2,4-triazole results in the formation of the bistriazolato complex [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-N3C2H2)(2)](+) (4) Successive protonation of the triazolato ligands in 4 leads to the complexes [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),-N3C2H2)(mu(2)-eta(1),eta(1 )-N3C2H3)](2+) (5) and [(eta(6)-C6Me6)(2)RU2(mu(2)-H)(mu(2)-eta(1),eta(1)-N3C2H2)(2)](3+) (6). The reaction of 1 with 1,2,3-triazole gives a 1:1 mixture of the bistriazolato complexes [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-N3C2H2)(2)](+) with parallel (7a) and anti-parallel (7b) coordination of the triazolato ligands. The single-crystal X-ray structure analyses of 2 (hexafluorophosphate salt) and 4 (tosylate salt) reveal for both complex types a ruthenium-ruthenium backbone being bridged by the two heterocyclic ligands with the N-N axis coordinated in a mu(2)-eta(1),eta(1)-fashion. A single-crystal X-ray structure analysis of title complex 1 (hexafluorophosphate salt) confirms the presence of three bridging hydride ligands with a Ru-Ru distance of only 2.47 Angstrom. (C) 1998 Elsevier Science S.A. All rights reserved. - PublicationMétadonnées seulementCarbon-carbon coupling reactions of but-2-yne on a triruthenium framework: synthesis and molecular structure of Ru-3(CO)(7)[NS(O)MePh] (HCMeCMeCMeCMeCO) and Ru-3(CO)(8)(CMeCMeCMeCMe)(1999)
; The cluster HRu3(CO)(9)[NS(O)MePh] (1) reacts with two equivalents of MeC=CMe in tetrahydrofuran at 60 degrees C to give the dienonyl derivative Ru-3(CO)(7)[NS(O)MePh] (HCMeCMeCMeCMeCO) (2), along with an isomer mixture of Ru-3(CO)(8)[NS(O)MePh] (HCMeCMe) (3). At 100 degrees C, the same reaction gives rise to the formation of the diendiyl cluster Ru-3(CO)(8)(CMeCMeCMeCMe) (4). The single-crystal structure analyses reveal for 2 a closed Ru-3 skeleton and for 4 an open Ru, framework. (C) 1999 Elsevier Science S.A. All rights reserved. - PublicationMétadonnées seulementA cluster containing a pyrazole ligand: [Ru3(?-H)(?-N2C3H3)(CO)10](2002)
; ; The title cluster decacarbonyl-1?4C,2?3C,3?3C-?-hydrido-2:3?2H:H-?-pyrazolyl-2:3?2N1:N2-triangulo-triruthenium, [Ru3(?-H)(?-C3H3N2)(CO)10], which contains a pyrazole ligand, was synthesized and characterized, both spectroscopically and crystallog., as a cyclohexane solvate. Crystals are monoclinic, space group I2/a, with a 14.2248(11), b 9.1670(5), c 59.834(5) Å, ? 90.380(9)°; Z = 8 (2 mols./Z), dc = 2.290; R = 0.041, Rw(F2) = 0.107 for 4743 reflections. The mol. structure is very similar to that of the known dimethylpyrazole deriv. [Ru3(?-H){?-N2C3HMe2-3,5}(CO)10]. [on SciFinder(R)] - PublicationMétadonnées seulementNew 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)
; 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. - PublicationMétadonnées seulementParallel coordination of hydrazine to diruthenium units: synthesis and molecular structure of the cationic complexes [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(2)(mu(2)-eta(1),eta(1)-H2NNH2)](2+) and [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-H2NNH2)(mu(2)-NH2)]( 2+)(1998)
; The dinuclear cation [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(3)](+) (1) reacts in aqueous solution with hydrazine to give the dicationic complexes [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(2)(mu(2)-eta(1), eta(1)-H2NNH2)](2+) (2) and [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-H2NNH2)(mu(2)-NH2)]( 2+) (3). The single-crystal X-ray structure analyses of 2 (tosylate salt) and 3 (triflate salt) reveal both complexes to contain an intact hydrazine ligand coordinated parallel (mu(2)-eta(1),eta(1)) to the diruthenium backbone, comprising a Ru=Ru double bond (2.69 Angstrom) in 2 and a Ru-Ru single bond (2.85 Angstrom) in 3. A single crystal of the mixed sulfate-hexafluorophosphate salt of [(eta(6)-C6Me6)(2)Ru-2(mu(2)-H)(mu(2)-eta(1),eta(1)-H2NNH2)(mu(2)-N2H3)] (2+) (4), isolated from the mother liquor of 2, suggests this hydrazido complex to be an intermediate in the reaction from 2 to 3. (C) 1998 Elsevier Science S.A. All rights reserved. - PublicationMétadonnées seulementRu-4(mu-CO)(CO)(9)(eta(4)-mu(4)-C6H4)(eta(2)-mu(1), mu(4)-PPhCH2CH2PPh2): an unusual pyrolysis product of Ru-3(CO)(10)(dppe) containing a benzyne ligand(2002)
; The thermal decomposition of Ru-3(CO)(10)(dppe) in refluxing benzene gives, in contrast to the pyrolysis of the dppm analogue, the tetranuclear cluster Ru-4(mu-CO)(CO)(9)(eta(4)-mu(4)-C6H4) (eta(2)-mu(1), mu(4)-PCH2CH2PPh2) (1) along with Ru-3 (CO)(9)(eta(2)-mu(1), mu(2)-C6H5)(eta(3)-mu(1), mu(2)-PPhCH2CH2PPb2) (2). The single-crystal structure analysis of 1 reveals a square-planar tetraruthenium skeleton containing a eta(4)-mu(4)-benzyne ligand as well as a eta(2)-mu(1), mu(4)-phosphinidene-phosphine ligand. (C) 2002 Elsevier Science B.V. All rights reserved.
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