Synthesis and Mesomorphism of Novel Chiral Triphenylene-Based Discotic Liquid Crystals

A series of new chiral triphenylene-based discotic liquid crystals with one or three chiral soft chains were synthesized through Mitsunobu reactions. Yields of the chiral discotic liquid crystals were achieved up to 84%. Chemical structures were confirmed by 1H NMR; and mesomorphism was studied by polarized optical microscopy as well as by differential scanning calorimetry. The mesomorphic studies have shown that 1) the chiral discogens have either hexagonal columnar or plastic columnar mesophases; and 2) the introduction of chirality to triphenylene-based discotic liquid crystals could widen mesophase range by lowering melting points. In addition, an unexpected odd-even effect of mesomorphism was observed.