Liquid-crystalline bisadducts of [60]fullerene.
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.
Campidelli
Stéphane
S
Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.
Vazquez
Ester
E
Milic
Dragana
D
Lenoble
Julie
J
Atienza Castellanos
Carmen
C
Sarova
Ginka
G
Guldi
Dirk M
DM
Deschenaux
Robert
R
Prato
Maurizio
M
D000588:Amines; D002264:Carboxylic Acids; D050091:Dendrimers; D037741:Fullerenes / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D044367:Phase Transition
D000588:Amines; D002264:Carboxylic Acids; D050091:Dendrimers; D037741:Fullerenes