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

New chiral, as well as racemic 1-methylalkyl terephthalidene-bis-aminocinnamates have been synthesized and their liquid-crystalline properties investigated. Generally, the chiral compounds possess the antiferroelectric S(O)* phase, whereas in the homologous series of racemates, the appearance of the S(O) phase depends on the length of the alkyl chain. For racemic compounds derived from 2-alkanols with an odd number of 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.