Low-melting nematic V-shaped 1,3,4-thiadiazoles – phase engineering using small substituents and mixtures of flexible chains

Abstract

V-shaped, shape-persistent molecules with a central 1,3,4-thiadiazole core and a bending angle of 160° have been synthesised and their thermotropic behaviour characterised by means of polarised optical microscopy, differential scanning calorimetry and X-ray diffraction. The V-shaped mesogens and the intermediate hockey-stick compounds exhibited enantiotropic nematic phases. The influence of fluorine or methyl substituents in the terminal phenyl rings, and alkyl chains in place of chains terminating with ethyl esters, has been studied in order to obtain structural information related to the stabilisation of the nematic phases.