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Deschenaux, Robert

Nom
Deschenaux, Robert
Affiliation principale
Fonction
Professeur ordinaire
Email
Robert.Deschenaux@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/384

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  • Publication
    Métadonnées seulement
    Liquid-Crystalline Janus-Type Fullerodendrimers Displaying Tunable Smectic-Columnar Mesomorphism
    (2007)
    Lenoble, Julie
    ;
    Campidelli, Stephane
    ;
    Maringa, Natacha
    ;
    Donnio, Bertrand
    ;
    Guillon, Daniel
    ;
    Yevlampieva, Natalia
    ;
    Deschenaux, Robert 
    Janus-type liq.-cryst. fullerodendrimers were synthesized via the 1,3-dipolar cycloaddtition of 2 mesomorphic dendrons and C60. By assembling poly(aryl ester) dendrons functionalized with cyanobiphenyl groups, displaying lamellar mesomorphism, with poly(benzyl ether) dendrons carrying alkyl chains, which display columnar mesomorphism, the authors could tailor by design the liq.-cryst. properties of the title compds. as a function of each dendron size. The liq.-cryst. properties were examd. by polarized optical microscopy, DSC, and x-ray diffraction. Depending on the dendrimer generations, smectic (SmC and/or SmA phases) or columnar (Colr-c2mm or Colr-p2gg phases) mesomorphism was obtained. The supramol. organization is governed by (1) the adequacy of the cross-sectional area of the dendrons, (2) the microsegregation of the dendrimer, (3) the deformation of the dendritic core, and (4) the dipolar interactions between the cyanobiphenyl groups. Comparison of the mesomorphic properties of 2 fullerodendrimers with those of model compds. (fullerene-free analogs) indicated that the C60 unit does not influence the type of mesophase that is formed. Mol. properties detd. in soln. (permanent dipole moment, specific dielec. polarization, molar Kerr const.) confirm that microsegregation persists in soln. and strengthen the models proposed for the structure of the mesophases. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Liquid-Crystalline Fullerodendrimers which Display Columnar Phases
    (2006)
    Lenoble, Julie
    ;
    Maringa, Natacha
    ;
    Campidelli, Stephane
    ;
    Donnio, Bertrand
    ;
    Guillon, Daniel
    ;
    Deschenaux, Robert 
    The title compds. were synthesized by applying the 1,3-dipolar cycloaddn. reaction of aldehyde-based poly(benzyl ether) dendrimers and sarcosine (N-methylglycine) to [60]fullerene (C60). The dendritic building blocks used to functionalize C60 displayed cubic and hexagonal columnar phases. The fullerene derivs. showed rectangular columnar phases of c 2. mm symmetry. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Supramolecular fullerene materials: dendritic liquid-crystalline fulleropyrrolidines
    (2005)
    Campidelli, Stephane
    ;
    Lenoble, Julie
    ;
    Barbera, Joaquin
    ;
    Paolucci, Francesco
    ;
    Marcaccio, Massimo
    ;
    Paolucci, Demis
    ;
    Deschenaux, Robert 
    [60]Fullerene-contg. liq.-cryst. dendrimers were synthesized from the first to the fourth generation by applying the 1,3-dipolar cycloaddn. reaction from a mesomorphic dendritic-type aldehyde deriv., sarcosine (N-methylglycine) or glycine and C60. The cyanobiphenyl unit was used as a liq.-cryst. promoter. With the exception of the first-generation fullerene dendrimer, which was found to be nonmesomorphic, all fullerene-based dendrimers gave rise to a smectic A phase. The liq.-cryst. fullerenes led to two different supramol. organizations within the smectic layers: for the second-generation dendrimers, the mols. are oriented in a head-to-tail fashion within the layers; for each mol. the cyanobiphenyl units point in the same direction. For the dendrimers of third and fourth generations, the dendritic core extends laterally, parallel to the layer planes; the mesogenic units are oriented above and below the dendritic core. For the aldehyde precursors, only one organization inside the layers was obtained, similar to the one obsd. for the third and fourth fullerene-based dendrimers. Cyclic voltammetry investigations displayed several one-electron and multielectron redn. processes; no significant interaction in the ground state between the fullerene and the dendrimer was noticed. The title compds. showed the typical electrochem. stability of fulleropyrrolidines. [on SciFinder(R)]