Síntese do primeiro cristal líquido iônico derivado da tristriazolotriazina

Abstract

This work describes the synthesis, characterization and the studies of the thermal and organizational properties of a new ionic liquid-crystalline material derived from tristriazolotriazine (TTT). Initially, the TTT was synthesized through a Huisgen reaction, which consists of reacting the cyanuric chloride with the 4-pyridyltetrazole. Afterwards, the previously synthesized TTT was alkylated with 4- (Bromomethyl) -1, 2-di (decyloxy) benzene. At the end of the alkylation, after purification of the final compound on a silica flash chromatographic column, using chloroform and methanol gradient, the existence of two different compounds, which were named TTT-6,3+ and TTT-12,6+, was discovered. Therefore, the final results of this work were two different molecules, one consisting of six flexible chains and three charges, and the other one consisting of twelve flexible chains and six charges. The synthesized compounds had their structure and purity confirmed by IR spectroscopy, 1H-NMR and melting point. The thermal and liquid-crystalline properties were investigated by MOLP, DSC, XRD and SAXS. These molecules were synthesized in order to obtain ionic liquid crystals with columnar discotic mesophase. This behavior was observed only for the compound TTT-12.6+, which presented liquid crystalline texture common for hexagonal columnar mesophase (Colh). The XRD and SAXS diffractograms could not confirm that the mesophase presented by this compound was, in fact, hexagonal. However, in the diffractograms obtained by XRD, the absence of the π-stacking type interactions between the disks was observed, showing the existence of a disordered columnar mesophase. Transition temperatures were confirmed by DSC analyses, where the mesophase transition was characterized by an exothermic peak in the cooling of the material from the isotropic liquid (143 oC). The absence of mesoformism for the compound TTT-6,3 + was initially detected by MOLP, where no liquid crystalline mesophase could be observed, and an apparent degradation of the sample was noticed. This result was confirmed by DSC, where the degradation from 125 oC was observed.