Thermotropic cholesterol-containing liquid

Thermotropic Cholesterol-Containing Liquid Crystalline Polymers... 

Polyisocyanides with cholesterol-containing pendant groups have been reported to display thermotropic liquid crystalline properties.223... 

V.P.Shibaev, N.A.Plate, and Ya.S.Freidzon, Thermotropic liquid crystalline polymers. Cholesterol containing polymers and copolymers, J.Polym.Sci., Polym.Chem.Ed. 17 1655 (1979). 

Reinitzer discovered liquid crystallinity in 1888 the so-called fourth state of matter.4 Liquid crystalline molecules combine the properties of mobility of liquids and orientational order of crystals. This phenomenon results from the anisotropy in the molecules from which the liquid crystals are built. Different factors may govern this anisotropy, for example, the presence of polar and apolar parts in the molecule, the fact that it contains flexible and rigid parts, or often a combination of both. Liquid crystals may be thermotropic, being a state of matter in between the solid and the liquid phase, or they may be lyotropic, that is, ordering induced by the solvent. In the latter case the solvent usually solvates a certain part of the molecule while the other part of the molecule helps induce aggregation, leading to mesoscopic assemblies. The first thermotropic mesophase discovered was a chiral nematic or cholesteric phase (N )4 named after the fact that it was observed in a cholesterol derivative. In hindsight, one can conclude that this was not the simplest mesophase possible. In fact, this mesophase is chiral, since the molecules are ordered in... 

Figure 1.53. A Cgo-cholesterol conjugate, representing the first fullerene-containing thermotropic liquid crystal.

Only a few examples of optically active ferrocene-containing thermotropic liquid crystals have been reported. Compounds (304) and (305) have been prepared by functionalizing ferrocene with a chiral fragment bearing an asymmetric carbon atom. Ferrocene derivative (304) showed an SmC phase, while for (305), SmC, SmA, TGBA, N, and blue phases (blue phases are referred to in Section 7.9.4.3.3) were obtained. " Ferrocene has also been substituted with a cholesterol derivative but the mesophases were not identified. ... 

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