A liquid crystalline supramolecular complex of C-60 with a cyclotriveratrylene derivative

Cyclotriveratrylene (CTV) derivatives substituted with 9 (1) or 18 (2) long alkyl chains have been prepared. Whereas no liquid crystalline behavior ha s been observed for 1, the CTV derivative 2 has mesomorphic properties. Ind eed, at room temperature compound 2 exhibits a nematic phase characterized by cybotactic groups with a local lamello-columnar order. Both CTV derivati ves 1 and 2 are able to form supramolecular complexes with C-60 in the soli d state. In both cases, the 2:1 host-guest species have been obtained as br own compounds. No liquid crystalline behavior was observed for the supramol ecular complex [C-60 subset of (1)(2)]. In contrast, observation of the bro wn product obtained from C-60 and the CTV derivative 2 directly after prepa ration by polarized optical microscopy revealed a fluid birefringent phase at room temperature. When the sample is heated above 70 degrees C, the bire fringence of the texture under the microscope disappears and the X-ray diff raction pattern is transformed into a pattern characteristic of a cubic pha se. For the first time in thermotropic liquid crystals, the space group of this cubic phase can be assigned as I4(1)32.