A Liquid Crystalline Supramolecular Complex of C60 with a Cyclotriveratrylene Derivative

Abstract

Cyclotriveratrylene (CTV) derivatives substituted with 9 (1) or 18 (2) long alkyl chains have been prepared. Whereas no liquid crystalline behavior has been observed for 1, the CTV derivative 2 has mesomorphic properties. Indeed, at room temperature compound 2 exhibits a nematic phase characterized by cybotactic groups with a local lamello-columnar order. Both CTV derivatives 1 and 2 are able to form supramolecular complexes with C60 in the solid state. In both cases, the 2:1 host-guest species have been obtained as brown compounds. No liquid crystalline behavior was observed for the supramolecular complex [C60 is included in (1)2]. In contrast, observation of the brown product obtained from C60 and the CTV derivative 2 directly after preparation by polarized optical microscopy revealed a fluid birefringent phase at room temperature. When the sample is heated above 70 degrees C, the birefringence of the texture under the microscope disappears and the X-ray diffraction pattern is transformed into a pattern characteristic of a cubic phase. For the first time in thermotropic liquid crystals, the space group of this cubic phase can be assigned as I4(1)32.

Liquid-crystalline fullerodendrimers

“…This approach represents an interesting way in the design of self-organized structures containing bulky functional units, and could be used for other functional groups which are not a priori adapted to be organized in nanoscale structures. The limitations of our concept, with respect to other approaches that have been reported, [40][41][42] lie in the efforts that need to be invested for the synthesis, purification and characterization of the liquidcrystalline dendrons and dendrimers used for the functionalization of C 60 . However, considering the enormous possibilities that dendritic compounds offer for tailoring the properties of the materials, such efforts are worthwhile.…”

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

“…The design of fullerene-containing thermotropic liquid crystals is based on covalent [7][8][9][10][11][12][13] or non-covalent 14 concepts. In the former approach, two reactions have been applied, the Bingel reaction 17 (i.e.…”

Isolation of the saddle and crown conformers of cyclotriveratrylene (CTV) oxime

“…24,25 CTV has been employed as a supramolecular building block to construct more complex cage-like cryptophanes. 26 CTV derivatives have also been studied for their mesomorphic properties 27 and are capable of forming liquid crystals by themselves 28 and as complexes with C60. 28 CTV has also been studied as a crystal engineering tecton giving network structures of unusual topology.…”