Campidelli Stéphane, Vazquez Ester, Milic Dragana, Lenoble Julie, Atienza Castellanos Carmen, Sarova Ginka, Guldi Dirk M, Deschenaux Robert, Prato Maurizio
Dipartimento di Scienze Farmaceutiche, Università degli Studi di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.
J Org Chem. 2006 Sep 29;71(20):7603-10. doi: 10.1021/jo0609576.
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.
一种基于第二代氰基联苯的树枝状大分子被用作液晶促进剂，以合成[60]富勒烯的介晶双加合物。通过带有羧酸官能团的液晶促进剂与相应的双氨基富勒烯衍生物缩合，得到了液晶反式-2、反式-3和赤道双加合物。还制备了富勒烯的单加合物用于比较。所有化合物都呈现出近晶A相。反式-2衍生物观察到一种无法识别的额外中间相。单加合物衍生物的超分子组织受空间位阻限制。实际上，为了实现有效的空间填充，富勒烯（约100 Ų）和介晶基团（每个介晶基团约22 - 25 Ų）的横截面积之间需要匹配。因此，单加合物形成双层近晶A相。双加合物的超分子组织主要由介晶基团和树枝状核心的性质和结构决定。因此，双加合物形成单层近晶A相。标题化合物是有前途的超分子材料，因为它们将液晶的自组装行为与富勒烯的性质结合在一起。
