Preparation and Mesomorphic Properties of tetramethylene-1,4-bis (p-oxybenzylidene p-substituted aniline)

摘要

A series of new dimesogenic compounds having two identical,terminal Schiff base type mesogens,and a central tetramethylene spacer were synthesized.Their thermotropic and mesomorphic properties of the compounds were investigated by differential scanning calorimetry and polarizing microscopy.The compounds with X= -F,-Cl,-Br,-CN and -OCH3 were enantiotropically nematic liquid crystal.In contrast,the compounds with X= -I and -CF3 were non-liquid crystal.The nematic forming efficiency of the groups was in the order of -CN > -OCH3 > -Br > -Cl > -F.