Synthesis and self-assembly of photoresponsive and luminescent polycatenar liquid crystals incorporating an azobenzene unit interconnecting two 1,3,4-thiadiazoles

Abstract

Novel polycatenar liquid crystals containing two 1,3,4-thiadiazole rings interconnected by an azobenzene central linkage have been synthesized and investigated by polarizing microscopy, DSC, X-ray scattering, SEM, UV-vis spectroscopy and photoluminescence measurements. These compounds can self-assemble into SmC, Col_hex/p6mm and Cub_I/Pmn liquid crystalline phases in the bulk states and form multistimuli responsive organogels in organic solvents. They have reversible photoresponsive properties in solution, liquid crystalline states and gel states. They also show fluorescence emission with large Stokes shift in solution and binding selectivity to Cu²⁺ among a series of cations in CH₃CN–CH₂Cl₂ solution.