Synthesis and characterization of non-symmetric dimeric ionic liquid crystals derived from 1,3,4-oxadiazole heterocycle

With the increase in manufacturing and consumption of electronic devices, such as organic light emitting diodes (OLED), organic field effect transistors (OFETs) and organic photovoltaic devices (OPVs), there was an increasing interest in the production of materiais that are renewable 1, flexible, cheaper, easier to synthesize, and with reduced energy consumption, when compared to conventional devices.2 Thereby the field of organic electronics has been developing, no longer being an area of pure academic interest, but enabling real day-today applications 1. Within the organic electronics, the liquid crystals (LCs) have been gaining notoriety due to their intermediary properties to the crystalline solid and the isotropic liquid, possessing long-range orientational order, characteristic of crystals, and flowing like liquids3 . LCs containing in their structure one, or more, heterocycles are being exploited as a result oftheir versatility,4 thus, dimeric LCs derived from 1,3,4-oxadiazole heterocycle have been studied because of the high quantum yield of luminescence and stability thermal5. ln order to study the p roperties of dimeric ionic LCs, the objective of this work was to synthesize and characterize two new molecules derived from 1,3,4-oxadiazole heterocycle, wherein each mesogenic group, oxaphenol (li) and oxapiridine (IV), were synthesized from the tetrazole (1), reacting it with the respective acyl chlorides in the presence of dry pyridine. The structural alteration was the variation of the size of the alkyl chain spacer of the mesogenic groups, in order to conclude that the presence of mesophases is affected by steric effects.