Thiazole linked covalent organic framework as fluorescent chemosensor for selective and sensitive detection of TNP

A new thiazole-linked covalent organic framework named as TA-DH COF comprised of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 2,5-dihydroxy-1,4-benzenedicarboxaldehyde has been synthesized, and its potential applications are exploded first time in fluorescence spectroscopy. TA-DH COF exhibits high crystallinity, porosity, robustness, as well as thermal and chemical stability. The thiazole formation is confirmed by 13C CP/MAS NMR and FT-IR spectroscopy. TA-DH COF displays a “turn off” fluorescence response at 423 nm towards TNP with a low detection limit of 0.17 μM in 1,4-dioxane. The good recovery in water samples implies its applications in practical samples to detect TNP. The absorption competition quenching (ACQ) mechanism, followed by inner filter effects (IFE) were synergistically responsible for fluorescence quenching. The present study demonstrates that TA-DH COF is a promising candidate as fluorescence chemosensor and opens an avenue to explore its potential applications to detect nitroaromatic compounds for pollution control and prevention.