Synthesis and characterisation of photochromic dithienylcyclopentene liquid crystal with thermal irreversibility

They were characterised by 1 H NMR, high resolution mass spectrometer, differential scanning calorimetry (DSC) and polarised optical microscopy (POM) with a hot stage. All of them exhibited excellent photochemically reversible isomerisation between the open-ring form and the closed-ring form in both organic solvents and LC media, resulting in the colour change between colourless and purple under different light irradiations.

The typical textures from POM showed that their isomers both had nematic phase and smectic phase with different colours. These compounds with bent shape were more sensitive to light than those of diarylethenes reported.