Core charge of imidazolium annulated triphenylene derivatives induces discotic columnar mesomorphism.

Thermotropic ionic liquid crystals have remained a relatively little studied group of materials despite their many potential applications as anisotropic ionic liquids and charge (ion and electron/hole) transporting materials. Particularly rare are core charged discotic liquid crystals because their synthesis is usually more involved, and their molecular design is less established. Presented here is a straightforward and versatile synthetic approach to imidazolium annulated triphenylene derivatives.

Self-Assembly of Board-Shaped Diketopyrrolopyrrole and Isoindigo Mesogens into Columnar π-π Stacks.

Diketopyrrolopyrrole and isoindigo are commercially important dyes that have recently found broad application as electron acceptor and light-absorbing groups in organic semiconductors. Their self-assembly into specific supramolecular structures to control optoelectronic properties has been hampered by limited options for substitution and their high propensity for crystallization. Reported here is a molecular design that directs self-assembly into previously elusive columnar mesophases of π-π stacking cores.

Stabilization of Columnar Liquid Crystal Phases via Arene-Perfluoroarene Interactions.

We report the synthesis of novel polycatenar dibenzopentacenequinones and that are designed to form columnar liquid crystalline phases. The mesomorphic properties of these compounds were investigated by polarized optical microscopy, differential scanning calorimetry, and powder X-ray diffraction. While compound exhibits two distinct columnar mesophases between 148 and 177 °C, fluorinated exhibits a columnar mesophase from 121 to 336 °C.

Synthesis and Self-Assembly of Liquid Crystalline Triphenylenedicarboxythioimides.

We report the synthesis and properties of a series of novel triphenylenedicarboxyimides and thioimides (-) to probe the effect of thionation on the formation of columnar mesophases. These materials display broad columnar mesophases and high clearing points and self-associate in solution to form dimers. Overall, thionation improved the self-assembly in solution and led to a stabilization of the columnar mesophase.

Synthesis and Characterization of Liquid-Crystalline Tetraoxapentacene Derivatives Exhibiting Aggregation-Induced Emission.

A series of new tetrakis(dialkoxyphenyl) dicyanotetraoxapentacene derivatives (1 a-c) were prepared by reaction of the appropriate terphenyl diols with tetrafluoroterephthalonitrile in good yields. Compounds 1 b and 1 c, which bear hexyloxy and decyloxy side chains, exhibited columnar hexagonal mesophases, as shown by polarized optical microscopy, variable-temperature powder X-ray diffraction, and differential scanning calorimetry. Single-crystal X-ray diffraction of methoxy-substituted 1 a revealed that the dicyanotetraoxapentacene core is highly planar, consistent with the notion that these molecules are able to stack in columnar mesophases.