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Stoeckli-Evans, Helen

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

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  • Publication
    Métadonnées seulement
    New Ru-3(CO)(12) derivatives with bulky diphosphine ligands: synthesis, structure and catalytic potential for olefin hydroformylation
    (2001)
    Diz, Enrique Lozano
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    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.
  • Publication
    Métadonnées seulement
    Tri- and tetranuclear mixed-metal clusters containing alkyne ligands: Synthesis and structure of [Ru3Ir(CO)(11)(RCCR ')](-), [Ru2Ir(CO)(9)(RCCR ')](-), and [HRu2Ir(CO)(9)(RCCR ')]
    (1999)
    Ferrand, Vincent
    ;
    Süss-Fink, Georg 
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    The tetrahedral cluster anion [Ru3Ir(CO)(13)](-) (1) reacts with internal alkynes RC=CR' to afford the alkyne derivatives [Ru3Ir(CO)(11) (RCCR')](-) (2: R = R' = Ph; 3: R = R' = Et; 4: R = Ph; R' = Me; 5: R = R' = Me) which have a butterfly arrangement of the Ru,Ir skeleton in which the alkyne is coordinated in mu(4)-eta(2) fashion. Under CO pressure they undergo fragmentation to give the trinuclear cluster anions [Ru2Ir(CO)(9)(RCCR')](-) (6: R = R' = Ph; 7: R = R' = Et; 8: R = Ph; R' = Me; 9: R = R' = Me), in which the alkyne ligand is coordinated in a mu(3)-eta(2) parallel fashion. Protonation of these trinuclear anions leads to the formation of the corresponding neutral hydride clusters [HRu2Ir(Co)(9)(RC=CR')] (10: R = R' = Ph; 11: R = R' = Et; 12: R = Ph; R' = Me; 13: R = R' = Me). The protonation of the butterfly anions 2 and 3, however, gives rise to the formation of the neutral tetrahedral clusters [HRu3Ir(CO)(11)(RCCR')] (14: R = R' = Ph and 15: R = R' = Et), respectively. The analogous clusters [HRu3Ir(CO)(11)(PhCCCH3)] (16) and [HRu3Ir(CO)(11)(CH3CCCH3)] (17) are only accessible from the reaction of the neutral cluster [HRu3Ir(CO)(13)] with the corresponding alkynes. The complexes 2, 4, 5, 6, 10, 12 and 15 are characterised by Xray structure analysis.
  • 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.