Voici les éléments 1 - 4 sur 4
  • Publication
    Métadonnées seulement
    Macrocyclic Effects in the Mesomorphic Properties of Liquid-Crystalline Pillar[5]- and Pillar[6]arenes
    (2013)
    Nierengarten, Iwona
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    ;
    Holler, Michel
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    Karmazin-Brelot, Lydia
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    Barbera, Joaquin
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    Nierengarten, Jean-Francois
    Whereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4) with paraformaldehyde in the presence of BF3·Et2O afforded exclusively the cyclopentameric pillar[5]arene deriv. (5), both cyclopenta- and cyclohexameric macrocycles 5 and 6 were obtained when the reaction of 4 with paraformaldehyde was performed at 45 °C in CHCl3 with FeCl3 as the catalyst. Treatment of compds. 4-6 with sodium azide provided the corresponding polyazides, to which a cyanobiphenyl building block was subsequently grafted to generate model compd. 1, pillar[5]arene 2, and pillar[6]arene 3, bearing two, ten and twelve mesomorphic subunits, resp. The liq.-cryst. and thermal properties of the compds. were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Comparison of the liq.-cryst. properties of macrocycles 2 and 3 with those of 1 revealed the strong influence of the macrocyclic pillar[n]arene core on the mesomorphic properties. Whereas only a monotropic mesophase was obsd. for 1, a broad enantiotropic mesophase was evidenced for both pillar[n]arene derivs. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Building liquid crystals from the 5-fold symmetrical pillar[5]arene core
    (2012)
    Nierengarten, Iwona
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    ;
    Holler, Michel
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    Nierengarten, Jean-Francois
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    Comparison of the liq.-cryst. properties of a pillar[5]arene core functionalized with 10 mesogenic cyanobiphenyl units with those of a corresponding model compd. revealed the strong influence of the macrocyclic pillar[5]arene core on the mesomorphic properties. [on SciFinder(R)]
  • Publication
    Accès libre
    Building liquid crystals from the 5-fold symmetrical pillar[5]arene core
    Nierengarten, Iwona
    ;
    ;
    Holler, Michel
    ;
    Nierengarten, Jean-Francois
    ;
    Comparison of the liquid-crystalline properties of a pillar[5]arene core functionalized with 10 mesogenic cyanobiphenyl units with those of a corresponding model compound revealed the strong influence of the macrocyclic pillar[5]arene core on the mesomorphic properties.
  • Publication
    Accès libre
    Self-organisation of dodeca-dendronized fullerene into supramolecular discs and helical columns containing a nanowire-like core
    ;
    Iehl, Julien
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    Holler, Michel
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    Peterca, Mihai
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    Wilson, Daniela A
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    Partridge, Benjamin E
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    Zhang, Shaodong
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    ;
    Nierengarten, Jean-Francois
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    Percec, Virgil
    Twelve chiral and achiral self-assembling dendrons have been grafted onto a [60]fullerene hexa-adduct core by copper-catalyzed alkyne azide "click" cycloaddition. The structure adopted by these compounds was determined by the self-assembling peripheral dendrons. These twelve dendrons mediate the self-organisation of the dendronized [60]fullerene into a disc-shaped structure containing the [60]fullerene in the centre. The fullerene-containing discs self-organise into helical supramolecular columns with a fullerene nanowire-like core, forming a 2D columnar hexagonal periodic array. These unprecedented supramolecular structures and their assemblies are expected to provide new developments in chiral complex molecular systems and their application to organic electronics and solar cells.