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Thermotropic Properties and Molecular Packing of Discotic Tristriazolotriazines with Rigid Substituents
Author(s) -
Rieth Thorsten,
Marszalek Tomasz,
Pisula Wojciech,
Detert Heiner
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201400034
Subject(s) - thermotropic crystal , mesophase , steric effects , solvatochromism , discotic liquid crystal , crystallography , chemistry , phase (matter) , liquid crystal , aryl , photochemistry , materials science , liquid crystalline , stereochemistry , organic chemistry , molecule , alkyl , optoelectronics
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. The structural study indicates that the thermotropic properties and organization of these systems can be well tuned by the steric demand of the aryl groups. Depending on the substituents, the compounds showed either a pure crystalline phase or a highly complex helical superstructure with a characteristic liquid‐crystalline phase at elevated temperatures. Changing the steric demand of the attached aryls allowed controlling the discs arrangement within the columnar helix, which is of great importance for the molecular orbital overlap.