Laterally Substituted 4-n-Alkylphenyl 4-n-Alkylbicyclo (2.2.2) octane-1-carboxylates

Abstract

Different substituents (fluoro, chloro, bromo, and cyano) have been separately introduced into the 2-position of the phenolic moiety of the 4-n-alkylphenyl 4-n-alkylbicyclo (2.2.2) octane-1-carboxylates to produce new series of low melting esters with large nematic ranges. In particular, thirty 4-n-alkyl-2-fluorophenyl and thirteen 4-n-alkyl-2-chlorlorophenyl 4-n-alkylbicyclo (2.2.2)octane-1-carboxylates are reported. The effect of the various lateral substituents on the clearing points and viscosities of the esters are rationalized in terms of steric interactions and the “shielding” properties of the bulky 1, 4 disubstituted bicyclo (2.2.2) octane ring. Mixtures of the 4-n-alkyl-2-fluorophenyl 4-n-alkylbicyclo(2.2.2)octane-1-carboxylates and cyanobiphenyls have useful electrooptical properties and have very low injected smectic tendencies.