One‐Step, Specific, and Fluorescent Sensing of pg‐Level TATP via Intramolecular Hydrogen Bond Breaking in Eu‐MOFs

ABSTRACT The design of zero‐background fluorescent sensing materials with specific functionalities is of great significance. Here, a special Eu‐MOF with nonfluorescent emission was designed and driven by H 2 O‐induced cascade reaction through modulating the number of hydroxyl groups in ligands to enhance the signal‐to‐noise ratio, sensitivity, and reaction speed toward triacetone triperoxide (TATP). It is found that only when the ligand was selected as 2,5‐dihydroxyterephthalic acid (DHTA), and with the introduction of H 2 O, the intramolecular hydrogen bond could be changed to a weaker intermolecular hydrogen bond, which would be interrupted and oxidized from the original enol structure to ketone, producing the fluorescence turn‐on response toward TATP. The special Eu‐MOF exhibited a high‐performance sensing for TATP, with fast response (<1 s), low limit of detection (LOD, 36.1 nM), superior selectivity even in the presence of 28 kinds of interferents, including the very similar hydrogen peroxide, strong robustness, and a practical detecting ability of 5 pg airborne TATP particle. Furthermore, we validated the practical feasibility of the specific Eu‐MOF by integrating a sensing chip into a portable detector, thereby confirming that this MOF exhibits considerable potential for trace‐level TATP detection in real‐world application scenarios. The present nonfluorescent MOF design strategy and the elaborate modulation of the conformation in MOF structure would provide a new pathway for the exploration of novel functional MOFs as well as high‐performance sensing methodologies.