LATERALLY 4-NITROBENZYLOXYCARBONYL SUBSTITUTED PHENYL BENZOATES - THEFIRST 2-RING MESOGENS WITH A LATERAL BRANCH CONTAINING A PHENYL RING

The synthesis and properties of laterally 4-nitrobenzyloxycarbonyl sub stituted phenyl benzoates are described; these compounds represent the first two-ring mesogens having a phenyl ring in the lateral branch. T he lengths of the terminal chains of the core carrying the branch have a great influence, as shown by the phase behaviour of two homologous series. Compounds having long alkyloxy groups exhibit enantiotropic sm ectic A phases. It should be emphasized that the mesophase thermal sta bility of these strongly branched derivatives can be higher than that of the laterally unsubstituted parent compound. Connecting two of the new mesogens by means of an aliphatic spacer results in a novel type o f twin molecule.