Synthesis and characterization of new H-shaped triphenylene discotic room-temperature liquid crystal tetramers by a copper-free click reaction

Abstract

Herein, four new H-shaped triphenylene discotic liquid crystal tetramers have been designed and synthesized using a copper-free [3+2] cycloaddition reaction between the triphenylene dimer and diazide compounds. To probe the molecular self-assembly and mesophase properties, the length and rigid spacers in diazide have been tailored. The tetramers 7 with a soft spacer display a room-temperature enantiotropic DLC mesophase, and X-ray diffraction confirms that they exhibit an unusual mesophase of a lamellar–hexagonal columnar phase (Col_hl). The results of the photophysical tests show that all the new H-shaped DLC tetramers display relatively high intensity photoluminescence properties.