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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
    The mixed-metal carbonyl cluster anion [Os3Ir(CO)(13)](-): Synthesis, structure, reactivity and catalytic activity in the carbonylation of methanol
    (1999)
    Süss-Fink, Georg 
    ;
    Haak, Susanne
    ;
    Ferrand, Vincent
    ;
    Stoeckli-Evans, Helen 
    The cluster anion [Os3Ir(CO)(13)](-) (1) was prepared in 50% yield by reaction of Os-3(CO)(12) with [Ir(CO)(4)](-). The single-crystal X-ray structure analysis of the bis(triphenylphosphoranylidene)ammonium salt shows 1 to consist of a tetrahedral metal core with one of the 13 carbonyl ligands being bridging. Protonation of 1 led to the neutral cluster HOs3Ir(CO)(13) (2), whereas the hydrogenation gave the cluster anion [H2Os3Ir(CO)(12)](-) (3). The catalytic activity of 1 for the carbonylation of methanol was studied. Using CH3I as co-catalyst, catalytic turnover numbers up to 1800 were obtained (140 degrees C, 30 bar) within 14 h. (C) 1999 Elsevier Science B.V. All rights reserved.
  • Publication
    Métadonnées seulement
    Electron-deficient triruthenium and triosmium clusters from the reaction of the cluster anions [HM3(CO)(11)](-) (M = Ru, Os) with tricyclohexylphosphine in methanol
    (1999)
    Süss-Fink, Georg 
    ;
    Godefroy, Isabelle
    ;
    Ferrand, Vincent
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    ;
    Kahlal, Samia
    ;
    Saillard, Jean-Yves
    ;
    Garland, Maria Teresa
    The reaction of Na[HRu3(CO)(11)] with an excess of tricyclohexylphosphine in methanol gives the neutral complex H2Ru3(CO)(6)(PCy3)(3) which is the first 44 e(-) triruthenium cluster reported. This highly electron-deficient species reacts with carbon monoxide to give the saturated 48 e(-) cluster Ru-3(CO)(9)(PCy3)(3). The electronic structure of the novel 44 e- cluster was established by EHT and DFT molecular orbital calculations of isoelectronic model compounds. The analogous reaction of [N(PPh3)(2)][HOs3(CO)(11)] with PCy3 in methanol affords the 46 e(-) cluster H2Os3(CO)(7)(PCy3)(3), the first trisubstituted derivative of H2Os3(CO)(10). In all cases methanol acts as source of protons for the formation of the hydride clusters. (C) 1999 Elsevier Science S.A. 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
    Site-selective carbonyl substitution in the mixed-metal cluster anion [H2Ru3Ir(CO)(12)](-): synthesis and characterization of phosphine, phosphite, arsine and stibine derivatives
    (1999)
    Süss-Fink, Georg 
    ;
    Haak, Susanne
    ;
    Ferrand, Vincent
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    The reaction of the mixed-metal carbonyl cluster anion [H2Ru3Ir(CO)(12)](-) with PPh3, PMe3, P(OPh)(3), AsPh3 or SbPh3 leads to the mono-substituted derivatives [H2Ru3Ir(CO)(11)L](-) (L = PPh3 1, L = PMe3 2, L = P(OPh)(3) 3, L = AsPh3 4, L = SbPh3 5). Protonation of the anions 1-5 gives the neutral trihydrido derivatives H3Ru3Ir(CO)(11)L (L = PPh3 6, L = PMe3 7, L = P(OPh)(3) 8, L = AsPh3 9, L = SbPh3 10). All new tetranuclear clusters invariably show a tetrahedral arrangement of the Ru3Ir skeleton, as predicted for 60 e systems. The ligand L is coordinated to one of the ruthenium atoms, except in the case of L = PMe3 where two substitution isomers are observed. While the anionic isomers [H2Ru3Ir(CO)(11)(PMe3)](-) (2) could not be separated, the corresponding neutral isomers H3Ru3Ir(CO)(11)(PMe3) (7) could be resolved by thin-layer chromatography. In isomer 7a, the phosphine ligand is coordinated to one of the ruthenium atoms, whereas in isomer 7b the PMe3 ligand is bonded to the iridium atom. The molecular structures of 1, 7b, 8 and 9 were confirmed by a single-crystal X-ray structure analysis. (C) 1999 Elsevier Science S.A. All rights reserved.
  • Publication
    Métadonnées seulement
    Carbon-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)
    Ferrand, Vincent
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    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.
  • 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.
  • 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
    Métadonnées seulement
    Triruthenium clusters containing vinyl ligands: synthesis and structure of Ru-3(mu(2)-CO)(2)(CO)(6)[mu(3)-NS)(O)MePh](mu(2)-eta(1),eta(2)-PhCH2C=CH 2), Ru-3(mu(2)-CO)(CO)(7)[mu(3)-NS(O)MePh](mu(3)-eta(1),eta(2)-(PrC)-C-n=CHP rn), Ru-3(mu(2)-CO)(CO)(7)[mu(3)-NS(O)MePh](mu(3)-eta(1),eta(2)-PhC=CHBun), and (mu(2)-H)Ru-3(CO)(6)(mu(2)-eta(1),eta(2)-PhC=CHPh)(mu(3)-eta(1),eta(2)-P hC CPh)[mu(3)-eta(1),eta(2)-NS(O)Me(C6H4)]
    (1997)
    Ferrand, Vincent
    ;
    Merzweiler, Kurt
    ;
    Rheinwald, Gerd
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    The electron-deficient cluster (mu(2)-H)Ru-3(CO)(9)[mu(3)-NS(O)MePh] (1) reacts with the terminal alkyne PhCH2C=CH to give the vinyl complex Ru-3(mu(2)-CO)(2)(CO)(6)[mu(3)-NS(O)MePh](mu(2)-eta(1),eta(2)-PhCH2C=CH2 ) (2). The analogous reaction with internal alkynes (RC=CR') affords the clusters Ru-3(mu(2)-CO)(CO)(7)[mu(3)-NS(O)MePh](mu(3)-eta(1),eta(2)-RC=CHR') (3: R = R' = Pr "; 4: R = Ph; R' = Bu ") in which the vinyl ligand has opened a Ru-Ru bond upon coordination the Ru-3 framework. In the case of diphenylacetylene, reaction with two equivalents of the alkyne, yields the vinyl-alkyne cluster (mu(2)-H)Ru-3(CO)(6)(mu(2)-eta(1),eta(2)-PhC=CHPh)(mu(3)-eta(1),eta(2)-P hC=CPh)[mu(3)-eta(1),eta(2)-NS(O)Me(C6H4)] (5) with ortho-metallation of the phenyl substituent of the sulfoximido cap. (C) 1997 Elsevier Science S.A.
  • Publication
    Métadonnées seulement
    Carbon-carbon coupling reactions on triruthenium clusters: synthesis and structure of Ru-3(CO)(9)[mu(3)-eta(3)-PhCCCC(H)Ph][mu(2)-NS(O)MePh] and Ru-3(mu(2)-CO)(CO)(7)[mu(3)-eta(3)-PhCCCC(H)Ph][mu(3)-NS(O)MePh]
    (1997)
    Ferrand, Vincent
    ;
    Gambs, Céline
    ;
    Derrien, Nadine
    ;
    Bolm, Carsten
    ;
    Stoeckli-Evans, Helen 
    ;
    Süss-Fink, Georg 
    The reaction of the electron-deficient cluster (mu(2)-H)Ru-3(CO)(9)[mu(3)-NS(O)MePh] (1) with para-nitrotolane gives, with coupling of two alkyne units and elimination of the para-nitrophenyl fragment, the trinuclear complexes Ru-3(CO)(9)[mu(3)-eta(3)-PhCCCC(H)Ph][mu(2)-NS(O)MePh] (2) and Ru-3(mu(2)-CO)(CO)(7)[mu(3)-eta(3)-PhCCCC(H)Ph][mu(3)-NS(O)MePh] (3). The resulting organic moiety, coordinated as mu(3)-eta(3)-5e-donor, is best considered as a butenynyl (PhC=C-C=C(H)Ph) ligand in 2 and as a butatrienyl (PhC=C=C=C(H)Ph) ligand in 3. From the reaction mixture, the two isomeric vinyl complexes Ru-3(mu(2)-CO)(2)(CO)(6)[mu(2)-eta(2)-PhC=C(H)(C6H4-p-NO2)][mu(3)-NS(O)M ePh] (4a) and Ru-3(mu(2)-CO)(2)(CO)(6)[mu(2)-eta(2)-(C6H4-P-NO2)-C=C(H)Ph]-[mu(3)-NS(O )MePh] (4b) complexes can also be isolated. (C) 1997 Elsevier Science S.A.