FLUOROSUBSTITUTED CHIRAL LIQUID-CRYSTALS DERIVED FROM (R)-2-(4-HYDROXYPHENOXY)PROPAN-1-OL

Two homologous series of (R)-2-(4-hydroxyphenoxy)propan-1-ol derived m aterials were synthesized; the 4'-pentylbiphenyl-4-ylcarbonyloxy)pheno xy]propanes and the 4'-pentylbiphenyl-4-ylcarbonyloxy)phenoxy]propanes with alkoxy groups from methoxy to hexyloxy. These materials all show ed thermotropic liquid-crystalline properties which illustrate the inf luence of the fluoro substituents, in giving reduced melting points, c learing points, and smectic A to chiral nematic transitions, relative to their non-fluoro-substituted parent system. Certain members of both series, especially the higher homologues, showed chiral nematic phase s at, or around, room temperature. The transition temperatures for bot h series are discussed in terms of the influence of the fluoro substit uent in relation to its position within the aromatic core.