Synthesis and Helical Twisting Power of Chiral Dopants having Trifluoromethyl Group at the Terminal Position

Abstract

New chiral dopants having a Irifluoromethvl group at the terminal position were synthesized using oplically active 2-phenylpropanoic acid or 4,4,4-trifluoro-3-phenylbulanoic acid. Chiral nematic liquid crystal mixtures were prepared by adding one weight percent of a clriral dopant into an achiral host liquid crystal. The helical pitches of the chiral nematic phases were measured using Cane-wedge cell. Some chiral dopants showed quilt large values of helical twisling power (HTP). Chiral dopanls having trifluoromethyl group at lhe terminal position showed relatively small HTP values. On the other hand, HTP values depended on the linkage between a core and a chiral moiety. The relationship between the molecular structures and the magnitude of HTP was discussed.