Synthesis and mesomorphic properties of some fluoro-substituted benzoates

Several series of fluoro-substituted benzoate liquid crystals have been syn thesized. The results showed that the SmA phase is enhanced with the increa sing of the degree of fluoro-substitution on the para- and meta-postion of the terminal phenyl groups. And the molecules which have same molecular str uctural formula show nearly the same melting points. It is also discussed a bout the effect of the eater bond's direction on the mesomorphic properties .