Highly Emissive Triazine-Linked Tetraarylbuta-1,3-diene-Based Porous Organic Polymers for Rapid Detection of Volatile Acids

Designing porous organic polymers (POPs) with aggregation-induced emission (AIE)-active building blocks is of paramount interest owing to their potential to produce highly luminescent POPs. Herein, two emissive POPs (named HVPOP and tBuVPOP) have been developed by taking advantage of the pronounced aggregation-induced emission (AIE) properties of partially twisted aryl-substituted buta-1,3-diene derivatives, which are linked through vinylene bond formation with trimethyl triazine. The synthesized POPs have been thoroughly characterized using FT-IR and solid-state NMR spectroscopy, and their porous nature is confirmed by nitrogen gas adsorption and desorption measurements. Owing to the presence of a bulky tert-butyl group in tBuVPOP, it exhibits relatively higher emission with an excellent photoluminescence quantum yield (27.3%) in the solid state compared to HVPOP (17.9%). Comprehensive photophysical and electrochemical studies of the synthesized POPs, along with their corresponding monomer units, are presented in this study. Additionally, these luminescent POPs are utilized for acid vapor sensing applications in the film state; specifically, tBuVPOP demonstrates an excellent response, displaying visible color changes to the naked eye and significant variations in emission intensity when exposed to various acid vapors over multiple cycles.