Abstract
The rapid and straightforward detection of explosive molecules is crucial for ensuring public safety and national security. Herein, a new series of conjugated polymers, referred to as the SP series, incorporating pentiptycene structures with organosulfur (sulfide and sulfonate ester) side chains, which is developed via sulfur(VI)-fluoride exchange (SuFEx) click chemistry. These polymers enhance the detection capabilities of nitroaromatic explosives through improved fluorescence quenching mechanisms. The method involved synthesizing β-sulfido sulfonyl fluorides via superbase-catalyzed thia-Michael reactions, introducing sulfonates through SuFEx conjugation, and assembling the polymers via palladium-catalyzed Sonogashira coupling. The SP-7 polymer, in particular, shows exceptional performance in explosives detection (DNT and TNT), achieving a >99% quenching efficiency within a few seconds, far surpassing existing polymer sensors. The fluorescence quenching dynamics via electron transfer in the SP-7 polymer are thoroughly elucidated using time-resolved photoluminescence and transient absorption spectroscopy, revealing that both static and dynamic quenching processes are highly effective. Remarkably, a straightforward yet powerful TLC-spotting-based technique is demonstrated that enables the rapid (<30 s) and selective detection of explosives under UV irradiation. This finding underscores the potential of SP series polymers in explosive practical detection, promising significant improvements in public security technologies.