Synthesis and mesomorphic properties of fluorinated liquid crystals obtained from optically active 2-fluoro-octanol

Abstract

Several homologues of semi-fluorinated liquid crystals, 4′-[(n-perfluoroalkyl)alkyloxy] phenyl 4-(2-fluoro-octyloxy) benzoates and 4′-(2-fluoro-octyloxy) phenyl 4-[(n-perfluoroalkyl) alkyl-oxy] benzoates have been synthesized. One set of the compounds, with the central carbonyl group conjugated to the terminal position carrying the non-chiral perfluoroalkyloxy tail, showed enhanced chiral smectic C behaviour, while the other set, with the central carbonyl group conjugated to the terminal position carrying the chiral 2-fluoro-octyloxy tail, exhibited enhanced smectic A behaviour. The mesomorphic properties of these novel fluorinated materials are reported and the effects of extent of fluorination are discussed.