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Stoeckli-Evans, Helen

Nom
Stoeckli-Evans, Helen
Affiliation principale
Fonction
Professeur.e émérite
Email
helen.stoeckli-evans@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/470
_
0000-0002-9960-3869

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  • 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
    Triruthenium-iridium clusters containing alkyne ligands: synthesis, structure, and catalytic implications of [(mu-H)IrRu3(CO)(11)(mu(3)-eta(2)-PhC CPh)] and [IrRu3(CO)(10)(mu(4)-eta(2)-PhC CPh)(mu-eta(2)-PhC = CHPh)]
    (1998)
    Ferrand, Vincent
    ;
    Süss-Fink, Georg 
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    The mixed-metal cluster [HIrRu3(CO)(13)] 1 reacts with one equivalent of disubstituted alkynes RC=CR to give [HIrRu3(CO)(11)(mu(3)-eta(2)-RC=CR)] (R = Ph 2; R = Me 3), with a second equivalent of the alkyne the clusters [IrRu3(CO)(10)(mu(4)-eta(2)-RC=CR)(mu-eta(2)-RC=CHR)] (R = Ph 4; R = Me 5) are obtained. The single-crystal X-ray structure analyses of 2 and 3 show these clusters to have a tetrahedral Ru3Ir framework containing the alkyne ligand coordinated in a parallel fashion over the Ru, face of the metal skeleton. In contrast, the clusters 4 and 5 consist of a butterfly arrangement of the Ru3Ir framework with the alkyne ligand coordinated to all four metal atoms, giving an overall octahedral Ru3IrC2 skeleton, as demonstrated by the single-crystal structure analysis of 4. Cluster I,is an excellent catalyst for the hydrogenation of diphenylacetylene to give stilbene (catalytic turnover number 990 within 15 min), clusters 2 and 1 are also catalytically active but seem to represent side-channels of the catalytic cycle.