SYNTHESIS AND LIQUID-CRYSTALLINE PROPERTIES OF A HOMOLOGOUS SERIES OFANTIFERROELECTRIC LIQUID-CRYSTALS AND THEIR RESPECTIVE RACEMATES

New chiral, as well as racemic 1-methylalkyl terephthalidene-bis-amino cinnamates have been synthesized and their liquid-crystalline properti es investigated. Generally, the chiral compounds possess the antiferro electric S(O) phase, whereas in the homologous series of racemates, t he appearance of the S(O) phase depends on the length of the alkyl cha in. For racemic compounds derived from 2-alkanols with an odd number o f carbon atoms, a S(O) phase is generally observed. On the other hand when the number of carbon atoms is even, a S(C) phase occurs. Moreover , in racemic 1-methylbutyl terephthalidene-bis-aminocinnamate, a S(C)- S(O)-S(C) reentrant phase sequence has been established.