Exploration of complex-based probe for pesticide residue detection: Specific recognition achieved via the synergistic effect of coordination water and supramolecular chains

The rational design of molecular fluorescent probes from transition metal complexes is a promising chemical strategy, yet its deployment for detection pesticide residues remains largely unexplored. Herein, a novel fluorescent probe for the pesticide PDM is fabricated from the Salen-Zn complex [Zn(3,5-Cl-Salnptn) (H 2 O)] (Zn-3,5-Cl-Salnptn). Experimental results demonstrated that Zn-3,5-Cl-Salnptn possesses exceptional selectivity, a high Stern-Volmer fluorescence quenching constant (Ksv = 4.2 × 10 4  M −1 ) and a low detection limit (1.13 μM) for PDM, and to the best of our knowledge, this is the first example of the complex-based probe for PDM detection. Theoretical calculations demonstrate that the axial coordination water, which forms a supramolecular chain structure through intermolecular hydrogen bonds, is essential for the specific recognition capability of the probe. This study not only provides a novel probe model for PDM pollution monitoring but also demonstrates the significant role of crystal engineering in optimizing the performance of pesticide residue probes.