Voici les éléments 1 - 10 sur 13
  • Publication
    Accès libre
    Nondestructive Room-Temperature Adsorption of 2,4,6-tri(2t-thienyl)-1,3,5-triazine on a Si-B Interface: High-Resolution STM Imaging and Molecular Modeling
    (2008)
    Makoudi, Y.
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    Palmino, F.
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    Duverger, E.
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    Arab, M.
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    Chérioux, Frédéric
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    Ramseyer, C.
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    Tschan, Mathieu J.-L.
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    Organic nanostructures on semiconductors are currently investigated but the surfaces are known to interact strongly with molecules. To reduce the molecule-surface interaction, we used the Si(111)-B √3 × √3R30°. Deposition of isolated 2,4,6-tri(2t-thienyl)-1,3,5-triazine, was achieved at room temperature without modification of their π skeleton. This fascinating arrangement, observed by STM, has been validated by full density functional theory computations onto the entire system. The theoretical results give a clear explanation for the specific adsorption sites of molecules on the substrate.
  • Publication
    Accès libre
    A Surprising Reaction of Trimethylphosphane with the Unsaturated Diruthenium Complex [(η6-C6Me6)2Ru22-H)3]+: Synthesis and Molecular Structure of the Cations [(η6-C6Me6)Ru2 (PMe3)32-H)3]+ and [(η6-C6Me6)2Ru2 (PMe3)22-H)(H)2]+
    (2007)
    Tschan, Mathieu J.-L.
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    Chérioux, Frédéric
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    Whereas aromatic or aliphatic phosphanes undergo cleavage of the P-C bond in the reaction with [(η6-C6Me6)2Ru22-H)3]+ to give phosphido-bridged diruthenium cations of the type [(η6- C6Me6)2Ru2(2-PR2)(μ2-H)2]+, trimethylphosphane surprisingly yields the substitution product [(η6-C6Me6)Ru2 (PMe3)32-H)3]+ (1), as well as the racemic intermediate [(η6-C6Me6)2Ru2(PMe3)22-H)(H)2]+ (2), in the form of the tetrafluoroborate salts. In complex 2, the hydrido ligands are fluxional in solution, as shown by variable-temperature 1H NMR spectroscopy. Cation 1 reacts with p-bromothiophenol to give the complex [(η6-C6Me6)2Ru2 (PMe3)32-(p-Br-C6H4)-S}(μ2-H)2]+ (3), isolated as the tetrafluoroborate salt.
  • Publication
    Accès libre
    Remarkable Anticancer Activity of Triruthenium-Arene Clusters Compared to Tetraruthenium-Arene Clusters
    (2007) ;
    Ang, Wee Han
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    Chérioux, Frédéric
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    Vieille-Petit, Ludovic
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    Juillerat-Jeanneret, Lucienne
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    Dyson, Paul J.
    The in vitro activity of a series of ruthenium clusters, [(η6-C6H6)(η6-C6Me6)2Ru3 (μ-H)3 (μ3-O)][BF4], [(η6-C6H6)(η6-1,4-iPrC6H4Me)(η6-C6Me6)Ru3 (μ-H)3 (μ3-O)][BF4], [(η6-C6H6)4Ru4 (μ-H)4][BF4]2, [(η6-C6H5Me)4Ru4 (μ-H)4][BF4]2 and [(η6-C6H6)4Ru4 (μ-H)3 (μ-OH)][Cl]2, has been evaluated against A2780 and A2780cisR ovarian carcinoma cell lines. Both triruthenium clusters are very active compared to ruthenium compounds in general, whereas the tetraruthenium clusters do not display significant cytotoxicities. Since the triruthenium clusters are known to form supramolecular interactions with arenes and other functions, it is possible that such interactions are also important with respect to their mode of biological activity. The X-ray structure analysis of [(η6-C6H5Me)4Ru4 (μ-H)4][PF6]2 is also reported.
  • Publication
    Accès libre
    Highly Selective Hydrogenation of Carbon-Carbon Multiple Bonds Catalyzed by the Cation [(C6Me6)2Ru2 (PPh2)H2]+: Molecular Structure of [(C6Me6)2Ru2 (PPh2)(CHCHPh)H]+, a Possible Intermediate in the Case of Phenylacetylene Hydrogenation
    (2006)
    Tschan, Mathieu J.-L.
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    Chérioux, Frédéric
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    The dinuclear cation [(C6Me6)2Ru2 (PPh2)H2]+ (1) has been studied as the catalyst for the hydrogenation of carbon-carbon double and triple bonds. In particular, [1][BF4] turned out to be a highly selective hydrogenation catalyst for olefin functions in molecules also containing reducible carbonyl functions, such as acrolein, carvone, and methyljasmonate. The hypothesis of molecular catalysis by dinuclear ruthenium complexes is supported by catalyst-poisoning experiments, the absence of an induction period in the kinetics of cyclohexene hydrogenation, and the isolation and single-crystal X-ray structure analysis of the tetrafluoroborate salt of the cation[(C6Me6)2Ru2 (PPh2)(CHCHPh)H]+ (2), which can be considered as an intermediate in the case of phenylacetylene hydrogenation. On the basis of these findings, a catalytic cycle is proposed which implies that substrate hydrogenation takes place at the intact diruthenium backbone, with the two ruthenium atoms acting cooperatively in the hydrogen-transfer process.
  • Publication
    Accès libre
    (μ-Diphenylphosphido-κP:P)-μ-hydrido-(μ-4-hydroxybenzenethiolato-κ2S:S)bis[(η6-hexamethylbenzene)ruthenium(II)] tetrafluoroborate
    (2006)
    Tschan, Mathieu J.-L.
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    Chérioux, Frédéric
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    Karmazin-Brelot, Lydia
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    The new triple-bridged dinuclear cation [(η6-C6Me6)2Ru22-p-S-C6H4-OH)(μ2-PPh2)(μ2-H)]+, isolated and characterized as the tetrafluoroborate salt, was prepared by reacting the precursor [(η6-C6Me6)2Ru22-H)22-PPh2)](BF4) and p-hydroxythiophenol in refluxing ethanol. The single-crystal X-ray structure analysis of [(η6-C12H18)2Ru22-S-C6H4-OH)(μ2-H){μ2-P(C6H5)2}](BF4) shows the formation of the meso form; despite the two stereogenic centres the complex is not chiral.
  • Publication
    Accès libre
    Synthesis, molecular structure and electrochemical properties of the star-shaped dinuclear complexes [Ru26-p-Me–C6H4-iPr)22-S-p-C6H4–C4H3S)3]+ and [Rh25-C5Me5)22-S-p-C6H4–C4H3S)3]+
    (2005-04-29)
    Chérioux, Frédéric
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    Sadki, Saïd
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    Comminges, Clément
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    The dinuclear cations [Ru26-p-Me–C6H4iPr)22-S-p-C6H4–Br)3]+ and [Rh(η5-C5Me5)(μ2-S-p-C6H4–Br)3]+ are found to undergo triple Suzuki coupling with 2- or 3-thiophene boronic acid to give [Ru26-p-Me–C6H4iPr)22-S-pC6H4–C4H3S)3]+ (1 and 2) and [Rh25-C5Me5)22-S-p-C6H4–C4H3S)3]+ (3 and 4), respectively. The star-like complexes are potential precursors for the insertion of dinuclear organometallic entities in the main chain of conjugated molecules thanks to their free thienyl moieties at their periphery. The electrochemical and optical properties of these new complexes have also been investigated.
  • Publication
    Accès libre
    Sulfur-containing trinuclear arene ruthenium clusters
    (2005)
    Tschan, Mathieu
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    Chérioux, Frédéric
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    The single-crystal X-ray structure analyses of [HRu3(C6H6)(C6Me6)23-SC6H4Me)(μ2-O)][BF4]2 ([1][BF4]2), [HRu3(C6H6)(C6Me6)23-SC6H4Me)(μ2-S)][PF6]2 ([2][PF6]2) and [H2Ru3(1,2,4,5-Me4C6H2)32-S)(Cl)]PF6([3][PF6]) are presented. The structures show the sulfur ligands to act as bridges between ruthenium atoms. In [1][BF4]2 and [2][PF6]2 the metallic core adopts a nido framework. However, in [3][PF6] the absence of a μ3-SR ligand combined with the presence of one terminal chloro unit gives rise to a closo metallic arrangement.
  • Publication
    Accès libre
    Synthesis and structural characterisation of new cationic dinuclear ruthenium(II) thiolato complexes of the type [Ru26-arene)2(μ-p-S–C6H4–Br)3]+
    (2004-02-20)
    Chérioux, Frédéric
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    Dinuclear dichloro complexes [Ru(C6H6)Cl2]2, [Ru(p-MeC6H4iPr)Cl2]2, [Ru(1,2,4,5-C6H2Me4)Cl2]2, and [Ru(C6Me6)Cl2]2 react in ethanol with p-bromothiophenol to give the corresponding cationic complexes [Ru2(C6H6)2(p-S–C6H4–Br)3]+ (1), [Ru2(p-MeC6H4iPr)2(p-S–C6H4–Br) 3]+ (2), [Ru2(1,2,4,5-C6H2Me4)2(p-S–C6H4–Br)3]+ (3), and [Ru2(C6Me6)2(p-S–C6H4–Br)3]+ (4), which can be isolated in quantitative yield as their chloride salts. X-ray structure analysis of these complexes shows that the nature of the arene ligand influences the folding of the p-S–C6H4–Br units. In 1, where the less hindered arene ligand is present, the three phenyl rings of the thiolato units are not constrained to a coplanar arrangement, whereas in 4 the C6Me6 forces the three phenyl rings to be in perfect planarity. Complexes 2 and 3 show an intermediary arrangement.
  • Publication
    Accès libre
    An iterative strategy for the synthesis of oligothiophenes by catalytic cross-coupling reactions
    An iterative strategy for the synthesis of new sulfur-functionalized oligothiophenes by Suzuki or Stille cross-coupling reactions was applied to the reaction of 4-bromo-tert-butylphenylthioether with thiophene derivatives. The planarity of the oligothiophenes obtained was confirmed by the single-crystal X-ray structure analysis of 2-(4-tert-butylthiophenyl)thiophene, which shows a potentially large electronic conjugation length.
  • Publication
    Accès libre
    Subsequent Hydride Substitution in (Arene)trihydridodiruthenium Complexes: Synthesis and Structure of Thiolato-Bridged Diruthenium Cations of the Type [H2(arene)2Ru2(p-X-C6H4-S)]+ and [H(arene)2Ru2(p-X-C6H4-S)2]+
    (2004)
    Tschan, Mathieu J.-L.
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    Chérioux, Frédéric
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    The cationic complexes [HRu26-arene)22-(p-X-C6H4)-S}2]+ and [H2Ru26-arene)22-(p-X-C6H4)-S}]+ (arene = 1,2,4,5-Me4C6H2 or C6Me6; X = Br and Me) are accessible in good yields from p-X-C6H4-SH with [H3Ru2(1,2,4,5-Me4C6H2)2][BF4] and [H3Ru2(C6Me6)2][BF4], respectively. The dibromo derivative [HRu2(C6Me6)2(p-Br-C6H4-S)2]+ is found to undergo double Suzuki coupling reactions with 3-thiophene boronic acid to give [HRu2(C6Me6)2(p-C4H3S-C6H4-S)2]+. This dibromo complex is a potential precursor for the insertion of dinuclear hydrido organometallic entities in the main chain of conjugated molecules.