Tristriazolotriazines with Azobenzene Arms ‐ Acidochromic Dyes and Discotic Liquid Crystals

Abstract

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.

Fused tetracyclic tris[1,2,4]triazolo[1,3,5]triazine as a novel rigid electron acceptor for efficient thermally activated delayed fluorescence emitters

“…Target compounds of TTT-PXZ and TTT-DMAC were synthesized by Huisgen original procedure, where threefold reaction of corresponding tetrazoles precursors of PXZ-TZ and DMAC-TZ with cyanuric chloride produced the tetracyclic tris [1,2,4]triazolo [1,3,5] triazine derivatives in high yields, respectively. 39 Both target compounds can be synthesized in large amount which will benet further commercialization. Their chemical structures were established by 1 H NMR, 13 C NMR spectroscopy and highresolution mass spectrometry.…”

“…Heptazine was the latest included in the nitrogen heterocyclic family having seven sp 2 hybridized nitrogen atoms in the fused ring, used as an acceptor in orange-red TADF emitter with high EQE max of 17.5%. 26 Tris [1,2,4]triazolo [1,3,5]triazine (TTT) is another heterocycle based on fused triazole and triazine moiety with nine sp 2 hybridized nitrogen atoms and a C 3 symmetry [5][6][7][30][31][32][33][35][36][37][38][39][40] which can provide an striking and remarkable alternative. It can be considered as a strong acceptor unit for the construction of donor acceptor (D 3 -A) TADF structure because of its rigid large electron decient plane.…”

New azobenzene liquid crystal with dihydropyrazole heterocycle and photoisomerization studies

“…Ester group, imino group, azo group, olefin bond and alkynyl group are usually selected as linkages for aromatic rings [ 1 ]. Azobenzene, as one of the traditional photochromic entities, can undergo reversible photoisomerization under ultraviolet and visible light with high thermal stability [ 2 – 4 ], so azo group is superior to other linkages like Schiffe's base, tolane and ester [ 5 – 7 ]. In recent years, liquid crystal materials of small molecules [ 8 , 9 ] and polymers [ 10 , 11 ] containing azobenzene photosensitive groups have been widely studied for their interesting optical properties.…”

Stacks of Azobenzene Stars: Self-Assembly Scenario and Stabilising Forces Quantified in Computer Modelling

“…There are several classifications of star-shaped azos: they may differ in (i) the number of arms (three [9,10,14,15,16,17,18,19,20], four [7,21,22], six [23,24,25], nine [26]), (ii) in their centres (nitrogen [9,19], phosphorus [27], silicon [28] or carbon atoms [21,22], benzene [14,16,20,29,30,31,32], polycyclic aromatic hydrocarbons [25,33], heterocyclic hydrocarbons [34,35,36,37], some chiral groups [6] or bio-active residues [38]), (iii) in the way azobenzenes are attached to the centre (covalently or noncovalently [39]), (iv) in their conformational rigidity (flexible or rigid), and (v) in their overall geometry (quasi-planar or 3D). Both the conformational rigidity and the shape of the star are closely related to the chemical nature of the star core.…”