The synthesis and mesomorphic properties of 4-n-alkoxyphenyl 4-[(4-n-alkoxy-2,3,5,6-tetrafluorophenyl)ethyl]benzoates

Abstract

4-n-Alkoxyphenyl4-[(4-n-alkoxy-2,3,5,6-tetrafluorophenyl)ethynyl]benzoates (compound A) are synthesised by a convenient method. These compounds exhibit only enantiotropic nematic phases and have very high clearing points. These compounds (As) can be transformed into corresponding ethane derivatives, via hydrogenation using a palladium catalyst (Pd/C), which exhibit monotropic nematic phases. The effect of the ethylene bridge (–CH₂CH₂–) on the mesomorphic behaviour is discussed.

Keywords:

• liquid crystal
• fluoro-substituted tolane
• monotropic nematic phase
• ethylene linking group
• bridge