Synthesis of cuprous iodide coordination polymers using pyridine carbohydrazide as ligands and their application in drug detection

Two coordination polymers named α-Copper(I) Iodide-3-pyridinecarbohydrazide (α-CuI-m-iah) and β-Copper(I) Iodide-3-pyridinecarbohydrazide (β-CuI-m-iah) with varying crystal structures and tunable emission wavelengths were obtained by adjusting the ligand (3-pyridinecarbohydrazide, m-iah) -to-metal clusters (CuI) ratio during the preparation process. α-CuI-m-iah was employed for the fluorescence detection of pesticide residues flumetralin, which demonstrated high selectivity, strong resistance to interference, and a wide linear detection range (1 μM-600 μM). It also exhibited a low detection limit (0.49 μM) and a fast response time, making it effective for detecting flumetralin in water samples with recovery rates ranging from 90.53 % to 97.13 %. The detection mechanism involved competitive absorption and fluorescence resonance energy transfer (FRET) between flumetralin and α-CuI-m-iah, resulting in a decrease in fluorescence intensity. This work not only introduces two coordination polymers with tunable emission behaviors but also highlights their potential for applications in pesticide residue detection.