Abstract: Using 8-hydroxyquinoline and 5-aminoisophthalic acid as raw materials, an azobenzene derivative, E-5-((8-hydroxyquinolin-5-yl)diazenyl)isophthalic acid (H3L), was synthesized through an azo reaction. A metal-organic framework (MOF) {[Y(L)(H2O)2]·2.25H2O}n was prepared by coordinating H3L with the rare earth ion Y3+,via a solvothermal synthesis method. The MOF was characterized using single-crystal X-ray diffraction analysis, thermogravimetric analysis, infrared spectroscopy, and powder X-ray diffraction analysis. Single-crystal X-ray diffraction analysis revealed that the MOF possesses a three-dimensional network structure with one-dimensional channels. Powder X-ray diffraction analysis demonstrated that the MOF exhibits excellent stability in various organic solvents and aqueous solutions with pH values ranging from 2 to 12. This MOF can serve as an excellent fluorescent sensor for accurately detecting various nitro compounds through fluorescence quenching. Experimental and theoretical calculations indicate that the luminescence quenching can be attributed to electron and resonance energy transfer between the MOF and the analytes. This study contributes to advancing research on MOF materials for their applications as fluorescent sensors in biological and environmental fields.

Key words: Metal-organic framework, Crystal structure, Fluorescence probe, Nitro compounds