Construction Of Crystalline Materials Based On Mixed Ligands And The Study On Fluorescence Sensing

Nowadays,with the rapid development of industry,excessive metal ions for instance Fe³⁺,Cu²⁺,CrO₄^2-,Cr₂O₇^2-,as well as organic small molecules such as nitro explosives and antibiotics,are emitted indiscriminate,which has a very serious impact on natural environment and human health.The random discharge of pollutants has a very serious impact on water body,the natural environment and human health.At present,expensive equipment for micro-detection of these substances is based on nuclear,electrochemistry and X-rays technologies.Most of them rely on complex operations,so the development of new detection methods and sensing materials is urgent.Metal-organic frameworks（MOFs）are a class of ordered and porous materials that have potential applications in many fields such as catalysis,separation,magnetism,storage,adsorption,drug delivery,fluorescence induction,etc.In recent years,luminescent MOFs materials have been deeply developed and applied in chemical and biological detection due to their selective,simple,sensitive,economical real-time detection of target analytes.Studies have shown that the design and synthesis of organic linkers are very important for the expected performance of luminescent MOFs.Zn-MOFs and Cd-MOFs with d¹⁰metal ions,can produce luminescence phenomenon under the interference of organic ligands.4,4’,4’’-Tricarboxyaniline（H₃NTB）with three carboxylic acid groups is a typicalπ-conjugated organic molecule,and it has superior potential in the formation of luminescence material aspects.Therefore,it is a good strategy to synthesize fluorescent materials with sensing properties by connecting Cd（Ⅱ）and NTB ligands to form a porous network.In this paper,four three-dimensional Cd-MOFs materials with different structures and excellent fluorescence properties had been successfully synthesized by solvothermal method:CUST-551,CUST-552,CUST-555,CUST-556 and CUST-557.X-ray single crystal diffraction,X-ray powder diffraction,infrared spectroscopy,ultraviolet-visible absorption spectroscopy,thermogravimetric analysis and elemental analysis were used to characterize their structures.Studies on the fluorescence properties of the materials showed that CUST-551 and CUST-552 have good selectivities and sensitivities for the detection of picric acid PA,Fe³⁺and Cr₂O₇^2-.CUST-555,CUST-556 and CUST-557 had good selectivities and sensitivities for the detection of nitrofurantoin NFT and nitrofurantoin NZF.Meanwhile,the stability,circulation and detection mechanism of the detection had been studied.