1,2,4-Tris(5-aryl-1,3,4-oxadiazolyl)-benzenes: novel λ-shaped fluorescent liquid crystals

Abstract

This study explores the development of λ-shaped liquid crystalline compounds with unique mesophase behaviour and fluorescence properties. We synthesized highly fluorescent λ-shaped mesogens incorporating oxadiazole moieties. Thermal characterization using DSC and POM reveals that tris(oxadiazolyl)benzenes (TOBs) with linear alkyl chains exhibit an enantiotropic mesophase over small temperature ranges, while branched derivatives show much broader enantiotropic mesophases. WAXS analysis indicates a hexagonal columnar arrangement. Optical studies demonstrate bright turquoise fluorescence with hypsochromic shifts in non-polar solvents. Our findings offer a new perspective on the design and application of liquid crystalline materials, potentially leading to more efficient and versatile optoelectronic devices.