Some Novel Cholesteric Esters Incorporating the 1,4-Disubstituted Bicyclo(2.2.2)octane Ring

Abstract

A chiral center has been introduced into different positions of one of the terminal alkyl chains of the known 4-alkylphenyl, 4-alkoxyphenyl and 4-alkyl-2-fluorophenyl 4-alkylbicyclo(2.2.2)octane-1-carboxylates^1.2 to produce seven homologous series of esters possessing cholesteric phases. Several of the esters exhibit enantiotropic cholesteric phases of tight pitch at and above room temperature, whilst others exhibit longer pitch enantiotropic cholesteric phases (sometimes at room temperature) which reflect light in the visible region of the electro-magnetic spectrum and are thermochromic.