Chemistry of Mesomorphic Compounds.

Abstract : This final report summarizes synthetical efforts in the chemistry of cholesteric liquid crystals and the temperature sensitivity of their visible selective reflection spectra. Eleven homologous series of alkanoates, omega-phenylalkanoates, alkyl carbonates, and S-alkyl thiocarbonates of cholesterol, cholest-5-en-3 beta-thiol, and 5 alpha-cholestan-3 beta-o1 were prepared and their mesomorphic properties investigated. In addition, numerous other derivatives of these and other 3 beta-sterols were synthesized in order to study the influence of various parameters, such as modified 17 beta-side chain, double bonds, and polar substituents on the mesomorphic properties. The research culminated with the discovery that S-cholesteryl 14-phenyltetradecanethioate reflects the spectral range of 420-600 nm within 0.07C and thereby allows the detection of temperature variations of 2 x 0.00002C.