Isophorone-based fluorescent probe for selective detection of explosives TNP/PYX with multi-scenario applications

The rapid detection of explosives is crucial for national security, public health, and environmental protection. In this study, a novel isophorone-based fluorescent compound, ( E )-2-(3-(2-(2-(dimethylamino)pyrimidin-5-yl)vinyl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile ( YMD ), was designed and synthesized. The structure of YMD was characterized by nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and X-ray single crystal diffraction. The detection limits for TNP and PYX were 13.88 μM and 15.59 μM, respectively. The probe exhibited a quick (within 10 s) and selective fluorescence quenching response to the explosives 2,4,6-Trinitrophenol (TNP) and 2,6-bis(picrylamino)-3,5-dinitropyridine (PYX), even in the presence of potential interferences. The mechanism can be attributed to synergistic effects involving multiple interactions, including photoinduced electron transfer (PET), inner filter effect (IFE), static quenching, and dynamic quenching. Remarkably, thanks to the excellent sensing properties of the YMD , it can be used for test strip testing. The YMD is capable of being applied to environmental water sample analysis and live intracellular imaging due to the mild detection system.