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  • Publication
    Métadonnées seulement
    Supramolecular fullerene materials: dendritic liquid-crystalline fulleropyrrolidines
    (2005)
    Campidelli, Stephane
    ;
    Lenoble, Julie
    ;
    Barbera, Joaquin
    ;
    Paolucci, Francesco
    ;
    Marcaccio, Massimo
    ;
    Paolucci, Demis
    ;
    [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)]
  • Publication
    Métadonnées seulement
    Dendritic liquid-crystalline fullerene-ferrocene dyads
    (: Molecular Diversity Preservation International, 2005)
    Campidelli, Stephane
    ;
    Perez, Laura
    ;
    Rodriguez-Lopez, Julian
    ;
    Barbera, Joaquin
    ;
    Langa, Fernando
    ;
    First- and second-generation ferrocene-based dendrimers, fullerene and a second-generation liq.-cryst. poly(aryl ester) dendrimer carrying four cyanobiphenyl units were assembled to elaborate polyfunctional materials displaying mesomorphic and electronic properties. The targeted compds. gave rise to enantiotropic smectic A phases and organized into bilayer structures within the smectic layers. Cyclic voltammetry investigations revealed oxidn. and redn. processes in agreement with the presence of both ferrocene and fullerene units. Finally, strong quenching of the fluorescence was obtained for the fullerene-ferrocene dyads suggesting efficient electron transfer from the ferrocene-based dendrimer to fullerene. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    Liquid-crystalline fullerene-ferrocene dyads
    (2004)
    Campidelli, Stephane
    ;
    Vazquez, Ester
    ;
    Milic, Dragana
    ;
    Prato, Maurizio
    ;
    Barbera, Joaquin
    ;
    Guldi, Dirk M.
    ;
    Marcaccio, Massimo
    ;
    Paolucci, Demis
    ;
    Paolucci, Francesco
    ;
    The 1,3-dipolar cycloaddn. reaction was used to assemble fullerene, ferrocene and a 2nd-generation liq.-cryst. cyanobiphenyl-based dendrimer. The targeted compd. displayed an enantiotropic smectic A phase from 40 to 135°. The d-layer spacing was detd. by x-ray diffraction, and is independent of temp. with a value of 95 Å. Mol. modeling and structural considerations suggested partial bilayer organization of the mesogenic mol. units within the smectic layers. Oxidn. or redn. processes of the basic components (ferrocene, fullerene, dendrimer) were studied by electrochem. techniques, and were in agreement with the structure. Photoinduced electron transfer from ferrocene to fullerene was identified, most likely with a through space mechanism. [on SciFinder(R)]