Liquid crystalline properties of new unsymmetrical compounds with benzothiazole core detected by TG/DSC-POM-XRD

Thermal properties of two azomethine liquid crystals with a benzothiazole core were synthesized and investigated by applied Mettler-Toledo AG equipment (TG/DSC). Azomethines with benzothiazole core was obtained by nucleophilic addition of benzothiazole-2-carboxaldehyde in N,N-dimethylacetamide (DMA) solution with 4-(heptadecafluoroctyl)aniline (BTA1) or 4-hexadecylaniline (BTA2). The differential scanning calorimetry (DSC) was employed to evaluate their phase transitional behavior. Variable heating and cooling rates were used to study liquid crystalline properties of azomethines with benzothiazole core. Compound BTA1 exhibited liquid crystalline properties, while BTA2 is non-mesogenic. Three or four endothermic DSC peaks were observed for both compounds during heating process with the rate 0.5?°C/min. The mesophase was identified and confirmed by XRD study and polarized optical microscopy (POM) too. The thermal stability was determined by thermogravimetric analysis (TG). The temperatures of 5% mass loss (T _5%) of BTA1 and BTA2 range from 212 to 317?°C in nitrogen.