Recent progress in triazine-based fluorescent probes for detecting hazardous nitroaromatic compounds

The rapid recognition of nitroaromatic compounds (NACs), especially in explosive detection, is a pressing concern in various sectors, including defence, homeland security, and environmental monitoring. The electron-withdrawing nature of NACs often interferes with photo-physical processes, making them challenging to detect yet ideal targets for fluorescent sensors. Particularly, trinitrophenol (TNP) and trinitrotoluene (TNT) have very strong electron-withdrawing properties and possess a low pKa value and distinct physicochemical features, making the fluorescence probes sensitive and selective detection. Recently, triazine-based fluorescence materials have become known as promising alternatives for designing sensors targeting these compounds. This review aims to provide a comprehensive overview of the advancements in developing and applying triazine-based fluorescent materials for detecting NACs in various environments. We discuss the fundamental principles behind fluorescence sensing and summarize the results of different triazine-based fluorescent materials, such as small molecules, metal-organic frameworks, and conjugated polymer frameworks, probes for detecting various NACs. We will also illustrate the diverse molecular structure, the effect of functional groups, and real-world applications of these sensors. This review will guide the future triazine-based fluorescent probes intended for NAC detection.