Design, mesomorphic properties, and supramolecular organization of [60]fullerene-containing thermotropic liquid crystals

Two concepts have been developed for the design of [60]fullerene-containing thermotropic liquid crystals, namely, the covalent and non-covalent concepts. In the covalent approach, C₆₀ was functionalized with liquid-crystalline addends (malonate and aldehyde derivatives) by applying either the Bingel reaction or the 1,3-dipolar cycloaddition reaction. In the non-covalent approach, a liquid-crystalline inclusion complex was obtained from mesomorphic cyclotriveratrylene (CTV) derivatives and C₆₀. All of the covalent C₆₀ derivatives showed smectic A phases. In one case, an additional nematic phase was detected. The [C₆₀(CTV)₂] complex gave rise to nematic-like and cubic phases. The covalent and non-covalent approaches demonstrate the various possibilities for C₆₀ to give rise to mesomorphic materials.