title: Liquid-crystalline bisadducts of [60]fullerene.
abstract: A second-generation cyanobiphenyl-based dendrimer was used as a liquid-crystalline promoter to synthesize mesomorphic bisadducts of [60]fullerene. Liquid-crystalline trans-2, trans-3, and equatorial bisadducts were obtained by condensation of the liquid-crystalline promoter, which carries a carboxylic acid function, with the corresponding bisaminofullerene derivatives. A monoadduct of fullerene was also prepared for comparative purposes. All the compounds gave rise to smectic A phases. An additional mesophase, which could not be identified, was observed for the trans-2 derivative. The supramolecular organization of the monoadduct derivative is governed by steric constraints. Indeed, for efficient space filling, adequacy between the cross-sectional areas of fullerene (approximately 100 A(2)) and of the mesogenic groups (approximately 22-25 A(2) per mesogenic group) is required. As a consequence, the monoadduct forms a bilayered smectic A phase. The supramolecular organization of the bisadducts is essentially governed by the nature and structure of the mesogenic groups and dendritic core. Therefore, the bisadducts form monolayered smectic A phases. The title compounds are promising supramolecular materials as they combine the self-organizing behavior of liquid crystals with the properties of fullerene.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Campidelli
authors.forename: Ester
authors.initials: E
authors.lastname: Vazquez
authors.forename: Dragana
authors.initials: D
authors.lastname: Milic
authors.forename: Julie
authors.initials: J
authors.lastname: Lenoble
authors.forename: Carmen
authors.initials: C
authors.lastname: Atienza Castellanos
authors.forename: Ginka
authors.initials: G
authors.lastname: Sarova
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Guldi
authors.forename: Robert
authors.initials: R
authors.lastname: Deschenaux
authors.forename: Maurizio
authors.initials: M
authors.lastname: Prato
mesh_terms: D000588:Amines; D002264:Carboxylic Acids; D050091:Dendrimers; D037741:Fullerenes / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D044367:Phase Transition
chemical_list: D000588:Amines; D002264:Carboxylic Acids; D050091:Dendrimers; D037741:Fullerenes