Novel bent-core mesogenic of 4-amino-triazole derivatives: synthesis, characterization and liquid crystalline study

摘要

The synthesis, characterization and mesomorphism of twelve new bent-shaped mesogens containing 4-amino-1,2,4-triazole as a central rigid core (II). are reported. The amino triazole derivatives were characterized by H-1, C-13 NMR spectroscopy, FT infrared, elemental analysis and one of them by mass spectrometry. The mesophase behavior was investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The homologues with short alkoxy terminal groups (II)(a-d) do not show any mesomorphic properties and only crystal to isotropic transition was observed by POM, whilst the analogue with the longest alkoxy terminal groups (II)(e-l) exhibit enantiotropic S(m)A, B-1, B-2, B-6 and B-7 phases with wide mesomorphic temperature ranges. The effect of the triazole ring and the length of the terminal alkoxy chains on the liquid crystals behavior of the compounds were discussed. (C) 2016 Elsevier Ltd. All rights reserved.