(223d) Sustainable Synthesis of Glassy Liquid Crystals As Advanced Optical Materials

Glass liquid crystals, GLCs, have found numerous potential optical device applications, including waveplates, non-absorbing polarizers, polarized lasers, notch filters, mirrors, and reflectors. From the molecular structure standpoint, cholesteric GLCs entail chemically bonding independent chiral and nematic pendant groups at an optimized stoichiometric ratio to volume-excluding cores. The more elegant approach incorporates both chiral and nematic characters in a single hybrid pendant, which substantially reduces the synthesis and purification efforts and hence facilitates process scale-up. To further promote chemical sustainability, p-hydroxybenzoic acid carrying a chemically activated phenolic hydroxy group toward esterification and etherification is adopted as a building block to obviate the protection-deprotection routines, thereby serving a synthesis scheme in fewer steps than previously possible with much improved atom economy, reaction mass efficiency, and other green chemistry metrics. The new strategies are generally applicable to the synthesis of nematic, cholesteric, and smectic GLCs comprising diverse combinations of volume-excluding core and mesogenic pendant.