Synthesis And Fluorescence Sensing Properties Of Novel Crystalline Microspore MOFs Materials

Metal-organic frameworks(MOFs)have attracted wide attention because of their porous structures,simple synthesis methods and various types.Judicious choice of transition metals and chromophoric organic ligands has rationally design various fluorescent MOFs with specific applications,which have been utilized as fluorescent sensor materials for the detection of explosive organic compounds,inorganic ions and organic small molecules.In this paper,three novel crystalline microporous MOFs materials were synthesized by using organic ligands with "tripod" structure as main ligands to coordinate with transition metals and lanthanide metals by solvothermal method.In order to determine the structure of the MOFs material,crystal data were collected and analyzed by single crystal X-ray diffraction.At last the structure was characterized by X-ray powder diffraction,infrared spectroscopy and elemental analysis.The thermostability of the synthesized MOFs was investigated by thermogravimetric analysis and the sensing properties were determined by fluorescence spectroscopy.The results of structural analysis show that the three new MOFs have three-dimensional microporous crystalline structures.The crystals constructed by the coordination of metal and organic ligands have high thermal stability and structural stability,and have chemical stability and luminescence stability in the process of fluorescence sensing.The analysis of the fluorescence performance of the synthesized MOFs materials mainly includes: solvent selection,sensing of nitro explosives,and reusability.Studies have shown that the synthesized MOFs materials have a fluorescence quenching response to nitroaromatic compounds,and the detection limit for trinitrophenol can reach the ppm level;In addition,the synthesized materials were recycled to verify their stability.They are proved to be sensitive and environmentally friendly detection materials with the fluorescence intensities remain above 90%.Finally,the fluorescence quenching mechanism was analyzed from perspective of structure characteristics of MOFs materials,frontier orbital theory and energy transfer,enriching the theoretical study of fluorescence quenching sensing of MOFs materials.