Discotic liquid crystalline materials for potential nonlinear optical applications: synthesis and liquid crystalline behavior of 1,3,5-triphenyl-2,4,6-triazine derivatives containing achiral and chiral alkyl chains at the periphery

As a novel approach to nonlinear optical materials, new octupolar discotic liquid crystalline materials 1,3,5-triphenyl-2,4,6-triazine derivatives containing achiral alkyl chains (5a) and chiral alkyl chains (5b) at the periphery were synthesized. The former exhibits an ordered hexagonal columnar mesophase, whereas the latter displays a rectangular columnar mesophase. The negative exciton splitting observed in the CD spectrum of a thin film of 5b suggests that it has a left-handed helical structure within the column.