Deuterated Liquid Crystals – practical synthesis of deuterium labeled 4-alkyl-4″-isothiocyanato-[1,1ʹ:4ʹ,1″]terphenyls

Liquid Crystals, especially materials exhibiting high birefringence are widely utilized in optoelectronic devices. The lifetime of these organic molecules is crucial to the correct operation of devices as they form the “heart” of the device. Exposition on electromagnetic radiation, in particular from UV–VIS region causes excitation of delocalized electrons and their transfer to higher energy levels. Then, photodegradation processes began to dominate inside organic material. Eventually, the operating parameters of the entire device are deteriorated. Herein we present new reinforced molecules which can be favor in the future applications. In this work we developed the synthetic methodology to a highly birefringent mono-, di-, and tri-fluorinated 4-alkyl-4″-isothiocyanato-[1,1ʹ:4ʹ,1″]terphenyls, where deuterium atoms are located at α and β positions of the terminal alkyl chains. These Deuterated Liquid Crystals have excellent isotopic purity ≥ 95%. The synthetic approach involves mainly deuteration reactions of CC bonds by using effective batch system and transformation of amine group (NH2) into isothiocyanate group (NCS) at the last step. These unique materials show higher photochemical stability vs non-deuterated analogs, while maintaining good optical anisotropy simultaneously. Results indicate a high potential use of Deuterated Liquid Crystals in many types of liquid crystalline devices.