摘要 |
<p>Compounds suitable for use in liquid crystal compositions (for example for use as light switching elements) have the formula: <CHEM> in R<1> is a straight or branched chain alkyl, alkoxy, alkanoyl, alkanoyloxy, alkoxycarbonyl, alkoxycarbonyloxy or alkoxyalkyl group, each containing from 1 to 20 carbon atoms; R<2> is hyrogen atom or a straight or branched alkyl, alkoxy or omega -halogen-substituted alkyl group, cyano, thioalkyl, alkoxy, alkanoyl, alkanoyloxy, alkoxycarbonyl or alkoxycarbonyloxy group, each containing from 1 to 15 carbon atoms; <CHEM> each independently represent a group <CHEM> (in which X is hydrogen, fluorine, chlorine atom or a cyano, methyl or trifluoromethyl group); m is 0 or 1; n is a natural number of 1 to 10; and the symbol * indicates that the carbon atom to which the symbol X is attached is an symmetric carbon atom.</p> |