Tristriazolotriazines with Azobenzene Arms ‐ Acidochromic Dyes and Discotic Liquid Crystals

Tristriazolotriazines with azobenzene substitution and peripheral alkoxy‐ or alkylamino chains were prepared from the corresponding aryltetrazoles and cyanuric chloride. These star‐shaped dyes are highly acidochromic. Alkoxy‐substitution allows reversible trans‐cis photoswitching. Compounds with a 3,4‐dialkoxy substitution are discotic liquid crystals that form broad and stable thermotropic mesophases. The thermal behavior was studied by DSC and polarizing optical microscopy. Tristriazozotriazines with three azobenzene arms and alkylamino or alkoxy side chains are prepared by Huisgen reaction. These stars shaped compounds are solvatochromic and acidochromic dyes, in which the protonation of all arms occurs simultaneously. Alkoxy‐Azo‐TTTs are efficient photoswitches. Peripheral 3,4‐dialkoxy substitution leads to mesomorphism, the LC phase is stable in daylight.