Novel Series of Enaminoketone Liquid Crystals Having Hexatic Smectic B Phase

Several homologous series of liquid crystals having an aminoketone mesogenic core (Liq. Cryst., 10, 593 (1991)), have been synthesized to derive some new wide-temperature untilted smectics. Compounds belonging to three of six novel series have the hexatic smectic B phase between smectic A and enantiotropic crystal smectic B phases. Eleven of them exhibit first order phase transition between smectic B phases, whereas for other compounds this phase transition is not detectable neither by DSC nor texture studies. Molecular modifications leading to further untitled hexatic compounds are suggested.