Construction And Fluorescent Properties On Rare Earth Ions-based Metal-Organic Frameworks

Metal-organic framework is a kind of porous material with periodic network structure formed by self-assembly of multi-dentate organic ligands such as nitrogen and carboxylic acid groups and metal ions.Because of its unique advantages in terms of adjustable pore size,skeletal structure design,and diversification of chemical functions,MOFs are widely used in fluorescence identification,catalysis,adsorption and separation,drug carriers,and other fields.Compared with traditional inorganic porous materials,MOFs have rich diversity in structure and function,and the infinite possibilities of structure of MOFs can be achieved through the controllability adjustment of organic ligands and metal ions.At the same time,the versatility of organic ligands and metal ions,as well as the application of post-modification methods,make MOFs rich in chemical functions.Among them,MOFs with fluorescent properties as a new type of detection materials have attracted the attention of scientists.They have shown great advantages such as high sensitivity,good selectivity,fast detection speed,stability and reliability in the field of detection and recognition.So MOFs are a kind of functional material with great potential application value.In this dissertation,MOFs with fluorescent properties were prepared,and the applications of the MOFs in the detection of heavy metal ions and nitro explosives were studied.Selecting triphenylamine tricarboxylic acid?H₃TCA?with fluorescent properties as organic ligand and interacting with rare earth ions Tb³⁺to prepare metal organic framework materials Tb-TCA which has optical properties.Through the effective energy transfer between the organic ligand triphenylamine tricarboxylic acid?H₃TCA?and Tb³⁺,Tb³⁺can be sensitized to emit its characteristic fluorescence.Combining powder diffraction,thermogravimetric analysis,solid UV and other characterization methods on Tb-TCA structural characterization,the fluorescent properties of Tb-TCA in the detection of heavy metal ions were studied,and the detection and identification of Fe³⁺by Tb-TCA was realized.Three isomorphs bimetallic organic frameworks Eu_xTb_1-x-TCA?x=0.24,0.40,0.59?with fluorescent properties were prepared by the interaction of the organic ligand triphenylamine tricarboxylic acid?H₃TCA?with the bimetallic ions Eu³⁺and Tb³⁺.Based on the antenna effect of rare earth ions,the energy transfers between the ligand and Eu³⁺and Tb³⁺simultaneously sensitizes the fluorescence emission of Eu³⁺and Tb³⁺.The structures of Eu_xTb_1-x-TCA were characterized by powder diffraction,thermogravimetric analysis,and solid UV spectrometry.The fluorescent properties of the complex Eu_xTb_1-x-TCA in the detection of nitro explosives were studied and the fluorescent detection of 2,4,6-trinitrophenol?PA?was achieved by Eu_xTb_1-x-TCA.