Chiral nematic liquid crystals with helix inversion from (R)-1,1′-binaphthyl and cholesteryl ester moieties

In this study, on the concept of intramolecular chiral conflict between the (R)-1,1'-binaphthyl and cholesteryl ester moieties, we have designed and synthesised a new liquid crystal (LC) (R)-dicholesteryl 6,6'-[1,1'-binaphthyl-2,2'-diylbis(oxy)]dihexanoate [(R)-DC]. A helix inversion could be observed for the chiral nematic liquid crystal (N*-LC) comprising the commercial nematic LC (N-LC) host SLC1717 and (R)-DC on heating. As a comparison, (S)-dicholesteryl 6,6'-[1,1'-binaphthyl-2,2'-diylbis(oxy)] dihexanoate [(S)-DC] was also prepared. Due to the intramolecular chiral superposition between the (S)-1,1'-binaphthyl and cholesteryl ester moieties, the N*-LC comprising SLC1717 and (S)-DC also exhibited excellent temperature sensitivity.