Four imidazole derivative AIEE luminophores: sensitive detection of NAC explosives

Abstract

Luminescent materials with aggregation-induced emission enhancement (AIEE) have received increasing attention as chemosensors. Four AIEE active imidazole derivatives with TPA moieties, M-MAP, M01-DMAC, M-IF, and M01-IF, have been developed for the sensitive detection of NAC explosives. The luminescence behaviors of compounds were systematically measured. In 90% THF/H₂O, 100–200 nm aggregated nanoparticles were formed with good regularity and stability. The intramolecular free rotations were restricted and emissions were enhanced within the aggregated state. The fluorescence of aqueous AIEE dispersions showed sensitive quenching by picric acid (PA), and the LOD was determined to be 30.99 nM for M-MAP. The intermolecular PIET mechanism was responsible for recognition and sensitive detection. Moreover, their AIEE luminescence behaviors respond weakly to other nitroaromatic compounds (NACs) or analogs. The quenching efficiencies, for M-MAP and M01-MAP, were almost consistent with the risk degrees of NACs. The test strips were easily prepared and the emission quenching effect was simply observed after contacting NACs. The potential of our new AIEEs was demonstrated for the fabrication of convenient and easily operating sensors for NACs.