A New [δ-PMo^VMo^VI₁₁O₄₀]-Based Hybrid as Multifunctional Fluorescent Sensor for Detecting Cations, Anions, and Antibiotics in Aqueous Solution

Abstract— A new POM-based hybrid, [δ-H₄PMo^VMo^VI₁₁O₄₀](L)₅·5H₂O (L = 4-methylpyridine-4-yl-1,8-naphthalene dicarboxylamide), was synthesized under hydrothermal conditions and characterized by IR spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy. This hybrid can acts as multifunctional fluorescent sensor to detect metal cation (Fe³⁺), anions (Cr₂O₇^2– and CrO₄^2–), and antibiotics (NFT = nitrofurantoin, NIT = nitrofurazone, OXY = oxytetracycline) in aqueous environment. The detection limits of the POM-based hybrid were 8.9×10^–5, 2.1×10^–4, 2.2×10^–4, 1.4×10^–4, 6.9×10^–4, and 6.1×10^–4 mol/L for Fe³⁺, Cr₂O₇^2–, CrO₄^2–, NIT, NFT, and OXY, respectively. Furthermore, the quenching mechanism between the POM-based hybrid and the different analytes can be regarded as energy competitive absorption.