Synthesis and Liquid Crystal Behaviour of Further 4,4″-Disubstituted 2'-Fluoro-1,1':4',1”-Terphenyls

Abstract
Further to earlier work on the liquid crystal properties of fluoro-1,1':4',1”-terphenyls1 we have now extended this series to include terminally fluoro-and cyano-substituted 2'-fluoro-1,1':4',1″-terphenyls, chiral 2'-fluoro-1,1':4',1″-terphenyls, and esters derived from 2'-fluoro-1,1':4',1”-terphenyls and incorporating the alkylcyclobutyl group. The preparations and transition temperatures for these series of compounds are presented and their transition temperatures and mesophase types are discussed. An interesting result from this work was the appearance of an S* C phase for one chiral homologue and of S c phases for the esters incorporating the alkylcyclobutyl group. The S c formation is attributed to the presence of the fluoro-substituent. Keywords: terphenyls, fluoroterphenyls, smectic C phases, cyclobutyl esters