Impact of Substitution Pattern and Chain Length on the Thermotropic Properties of Alkoxy-Substituted Triphenyl-Tristriazolotriazines.

Tristriazolotriazines (TTTs) with a threefold alkoxyphenyl substitution were prepared and studied by DSC, polarized optical microscopy (POM) and X-ray scattering. Six pentyloxy chains are sufficient to induce liquid-crystalline behavior in these star-shaped compounds. Thermotropic properties of TTTs with varying substitution patterns and a periphery of linear chains of different lengths, branching in the chain and swallow-tails, are compared.

Synthesis, Thermal, and Optical Properties of Tris(5-aryl-1,3,4-oxadiazol-2-yl)-1,3,5-triazines, New Star-Shaped Fluorescent Discotic Liquid Crystals.

The synthesis of tris(aryloxadiazolyl)triazines (TOTs), C -symmetrical star-shaped mesogenes with a 1,3,5-triazine center, 5-phenyl-1,3,4-oxadiazole arms, and various peripheral alkoxy side chains is reported. Threefold Huisgen reaction on a central triazine tricarboxylic acid and suitable aryltetrazoles yields the title compounds. Selected analogues with a benzene center are included in this study and allow for an evaluation of the impact of the central unit on the physical properties.

Isomerisation of Liquid-Crystalline Tristriazolotriazines.

Star-shaped discotic liquid crystals with columnar superstructures constitute a highly interesting class of organic materials. Phenyl-substituted tris[1,2,4]triazolo-[1,3,5]triazine, prepared by a Huisgen reaction of phenyltetrazole and cyanuric chloride, represents an excellent core for discotic liquid crystals (DLCs). The thermal stability is not perfect, at temperatures above the clearing point, a successive threefold isomerization leads to a highly planar, C -symmetrical isomer, which mainly differs in the orientation of the aryl substituents to the centre of the molecule.

Thermotropic properties and molecular packing of discotic tristriazolotriazines with rigid substituents.

Tristriazolotriazines with a threefold dialkoxyaryl substitution have been prepared by Huisgen reaction of cyanuric chloride and the corresponding tetrazoles. Although these dyes show a negative or inverted solvatochromism of the UV/Vis absorption, their fluorescence is strongly positive solvatochromic. These discotic fluorophores are also emissive in their solid state and in their broad liquid-crystalline mesophase.

5-Pentyl-1H-tetra-zole.

The title compound C(6)H(12)N(4), is one of a few known tetra-zoles with an alkyl chain in the 5-position. The asymmetric unit contains two independent mol-ecules. The mol-ecules are linked by N-H⋯N inter-actions into chains with graph-set notation D(2) and C(2) (2)(8) along [010].