Voici les éléments 1 - 10 sur 29
  • Publication
    Métadonnées seulement
    Synthesis and characterization of tetrahedral Ru3O clusters with intrinsic framework chirality: a chiral probe of the intact cluster catalysis concept. [Erratum to document cited in CA144:088385]
    (2006)
    Vieille-Petit, Ludovic
    ;
    ; ;
    Ward, Thomas R.
    ;
    ;
    Labat, Gaeel
    ;
    Karmazin-Brelot, Lydia
    ;
    Neels, Antonia
    ;
    Buergi, Thomas
    ;
    Finke, Richard G.
    ;
    Hagen, Collin M.
    On page 6112, Figure 9 was missing and Figure 11 appeared twice. The correct Figure 9 is given. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Synthesis and Characterization of Tetrahedral Ru3O Clusters with Intrinsic Framework Chirality: A Chiral Probe of the Intact Cluster Catalysis Concept
    (2005)
    Vieille-Petit, Ludovic
    ;
    ; ;
    Ward, Thomas R.
    ;
    ;
    Labat, Gaeel
    ;
    Karmazin-Brelot, Lydia
    ;
    Neels, Antonia
    ;
    Buergi, Thomas
    ;
    Finke, Richard G.
    ;
    Hagen, Collin M.
    Triruthenium mixed-ligand tetrahedral oxo-capped clusters with framework chirality were prepd. by redn. of areneruthenium triaqua dications followed by capping with areneruthenium dimer as racemic mixts.; diastereomeric mixts. were prepd. using chiral ligand; the prepd. complexes hydrogenate 2-acetamidoacrylate with no ee. Reaction of ArRuCl(?-Cl)2ClRuAr and Ar1RuCl(?-Cl)2ClRuAr1 with Ag2SO4 in aq. soln. gave mixt. of [ArRu(OH2)3]2+ and [Ar1Ru(OH2)3]2+, which upon NaBH4 redn. afforded mixed-ligand binuclear complex Ar1Ru(?-H)3RuAr (4, Ar = ?6-C6Me6, Ar1 = ?6-cymene). Reaction of 4 with Ar2RuCl(?-Cl)2ClRuAr2 and H2O gave the trinuclear cluster [(ArRu)(Ar1Ru)(Ar2Ru)(?3-O)(?-H)3]+ (rac-5, Ar2 = ?6-C6H6). Diastereomeric complexes [(ArRu)(Ar1Ru)(Ar*Ru)(?3-O)(?-H)3]+ [(S,R)-7, (R,R)-7; Ar* = (R)-1-phenylethanol] were prepd. by reaction of 4 with [Ar*RuCl(?-Cl)2ClRuAr*] (6). Analogous complex [(ArRu)(Ar1Ru)(Ar3Ru)(?3-O)(?-H)3]+ (8) was prepd. as a racemic mixt. from known (S,S)-Ar3RuCl(?-Cl)2ClRuAr3 [Ar3 = Et (R)-N-acetyl-?-aminobenzeneacetate]; the complex 8 was sepd. into diastereomers by chromatog., the racemization being caused by epimerization of the chiral ?-carbon. The enantiopure diastereomeric triruthenium clusters [(ArRu)(Ar1Ru)(Ar4Ru)(?3-O)(?-H)3]+ [(S,S)-17, (R,S)-17; Ar4 = (R)-N-acetyl-?-aminobenzeneethanol isobutyrate] were finally prepd. from (S,S)-Ar4RuCl(?-Cl)2ClRuAr4 and 4. The chiral Ru3O framework was evidenced by x-ray crystallog., by CD in the UV and IR regions, and by chiral shift reagents in the NMR spectra. To bring evidence for or against the hypothesis of catalytic hydrogenation by intact trinuclear arene ruthenium clusters contg. an oxo cap, catalytic hydrogenation of Me 2-acetamidoacrylate catalyzed by complexes 13 was performed; the complexes showed low catalytic activity and no asym. induction. [on SciFinder(R)]
  • 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
    ;
    ;
    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
    Ru-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)
    Diz, Enrique Lozano
    ;
    Neels, Antonia
    ;
    ;
    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.
  • Publication
    Métadonnées seulement
    A cluster containing a pyrazole ligand: [Ru3(?-H)(?-N2C3H3)(CO)10]
    (2002)
    Diz, Enrique Lozano
    ;
    Neels, Antonia
    ;
    ; ;
    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)]
  • Publication
    Métadonnées seulement
    New benzotriazole derivatives as multifunctional ligands
    (2002)
    Thomas, Christophe M.
    ;
    ;
    Neels, Antonia
    ;
    ;
    New multifunctional ligands based on the benzotriazole unit were synthesized by condensation of hydroxymethylbenzotriazole with carboxylic acid derivs. of pyridine, PPh3, ferrocene and thiophene. The coordination properties of these ligands towards Co, Rh and Ir were studied. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Reactions 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) ;
    Godefroy, Isabelle
    ;
    Faure, Matthieu
    ;
    Neels, Antonia
    ;
    The cluster anion [HRu3(CO)(11)](-) (1) reacts with dicyclohexylphosphine in THF solution to give the anionic derivative [HRu3(CO)(8)(PCy2)(2)](-) (2), protonation of which yields the neutral cluster H2Ru3(CO)(8)(PCy2)(2) (3) and, in the presence of excess phosphine, HRu3(CO)(7)(PCy2)(3) (4). In protic methanol as reaction medium, the reaction of 1 with HPCy2 gives directly the neutral complex H2Ru3(CO)(6)(PCy2)(2)(HPCy2)(2) (5). together with 4. The single-crystal structure X-ray analysis of 3 shows a closed triangular Ru, framework. Tho electron count is in accordance with the EAN rule, but the structure analysis of 5 reveals an open, almost linear Ru, skeleton, which is electron-deficient with respect to the EAN rule.
  • Publication
    Accès libre
    Nucleophilic addition reactions on the electron-deficient cluster dication [H4Ru4(C6H6)4]2+ : synthesis and structural characterisation of the water-soluble cluster cations [H3Ru4(C6H6)4 (CO)]+ and [H3Ru4(C6H6)4 (OH)]2
    (2001)
    Chérioux, Frédéric
    ;
    Maisse-François, Aline
    ;
    Neels, Antonia
    ;
    ;
    The electron-deficient (58e) cluster cation [H4Ru4(C6H6)4]2+1 was found to react in aqueous solution with simple nucleophiles to give electron-precise (60e) clusters. With carbon monoxide, the cluster cation [H3Ru4(C6H6)4(CO)]+3 is formed. The reaction with water needs NaN3 as catalyst and yields the cluster dication [H3Ru4(C6H6)4 (OH)]2+4a; the reaction with alcohols leads to the analogous clusters [H3Ru4(C6H6)4 (OR)]2+ (R = Me: 4b, R = Et: 4c, R = PhCH2: 4d, R = Ph: 4e, R = 4-EtC6H4: 4f). The single-crystal X-ray structure analyses of the chloride salts of 3 and 4a reveal a tetrahedral Ru4 metal core. Each ruthenium atom is coordinated by a η6-benzene ligand, while the carbonyl or hydroxo ligands are found as µ3 capping ligands over a triangular face of the Ru4 tetrahedron.
  • Publication
    Métadonnées seulement
    Reactions of the cationic complex [(eta(5)-C5Me5)(2)Ir-2(mu(2)-H)(3)](+) with nitrogen-containing heterocycles in aqueous solution
    (2001)
    Faure, Matthieu
    ;
    Onidi, Anne
    ;
    Neels, Antonia
    ;
    ;
    The dinuclear cation [(eta (5)-C5Me5)(2)Ir2(mu (2)-H)(3)](+) (1) reacts in aqueous solution with pyrazole and 4-methylpyrazole to give the bispyrazolato complexes [(eta (5)-C5Me5)(2)Ir-2(mu (2)-H)(mu (2)-eta (1),eta (1)-N2C3H2R)(2)](+) (R = H, 2; R = Me, 3). The reaction of complex 1 with 1,2,4-triazole results in the formation of the bistriazolato complex [(mu (5)-C5Me5)(2)Ir-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 (5)-C5Me5)(2)Ir-2(mu (2)-H)(mu (2)-eta (1),eta (1)-N3C2H2)(mu (2)-eta (1),eta (1)-N3C2H3)](2+) (5) and [(eta (5)-C5Me5)(2)Ir-2(mu (2)-H)(mu (2)-eta (1),eta (1)-H3C2H3)(2)](3+) (6). The reaction of 1 with 1,2,3-triazole gives a 1:1 mixture of the bistriazolato complexes [(eta (5)-C5Me5)(2)Ir-2(mu (2)-H)(mu (2)-eta (1),eta (1)-N3C2H2)(2)](+) with parallel (7a) and antiparallel (7b) coordination of the triazolato ligands. The X-ray structure analysis of 3 reveals a diiridium backbone which is bridged by two pyrazolato ligands, the N-N axis being coordinated in a mu (2)-eta (1),eta (1) fashion. (C) 2001 Elsevier Science B.V. All rights reserved.
  • 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
    ;
    ;
    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.