Synthesis and Characterization of Heterocyclic Compounds-Based Liquid Crystals

This research includes the synthesis, characterization, and investigation of liquid crystalline properties of new rod-shaped liquid crystal compounds ۱,۴-phenylene bis(۲-(۵-(four-alkoxybenzylidene)-۲,۴-dioxothiazolidin-۳-yl)acetate), prepared thiazolidine-۲,۴-dione (I) by the thiourea reaction with chloroacetic acid and water in the presence of the concentrated hydrochloric acid. The n-alkoxy benzaldehyde (II)n synthesized from the reacted ۴-hydreoxybenzaldehyde and n-alkyl bromide with potassium hydroxide, and then the compound (I)  was reacted with (II)n in the presence of piperidine to produce compounds (III)n. Also, hydroquinone was converted into a corresponding compound (IV) by refluxing with two moles of chloracetyl chloride in pyridine and DMF. After that, the compounds (III)n was interacted with sodium acetate to form compounds (V)n. FT-IR and ۱H-NMR spectroscopy were really used to determine the structures of the produced substances. By using the polarized optical microscopy, these mesogens' mesomorphic characteristics were studied (POM). The produced compounds displayed enantiotropic liquid crystal phases, while the substances (V)۶–۸ displayed a smectic enantiotropy in a variation on the nematic phases.