Design And Synthesis Of Lanthanide Metal-Organic Frameworks Based On Nitrogenous Carboxylic Ligands With Fluorescence Sensing Properties

The contents of some ions or small molecules in the organism can act as indicators of some disease or physiological state.It is very important to realize the fast and accurate detection.Compared with traditional detection methods,fluorescence detection emerges as a new method with the advantages of specificity,high sensitivity,fast response,low detection limit and repeatability.Based on the high quantum efficiency in the visible light range,the fluorescence detection based on the luminescence of lanthanide metals can realize visual detection,which has become a research hotspot in recent years.Metal-organic frameworks(MOFs)are crystal materials with an ordered pore structure,constructed by metal ions or metal clusters and organic ligands through the self-assembly coordination.Luminscent MOFs possesses not only the advantages of frameworks like porous structure and strong stability,but also unique luminescent properties including rich luminescent mechanism,wide emmision range and strong designability for different functions,making it a potential material for fluorescence detection field.Lanthanide MOFs can emit the characteristic fluorescence of rare earth ions.By selecting organic ligands with suitable triplet level,MOFs with excellent luminescence properties can be obtained.The porous properties of MOFs can be used to aggregate the analytes,thus obtaining more sensitive detection effects.Choosing ligands with functionalized sites can specially detect analyte by the host-guest interaction.Based on the organic ligand H3TATB(4,4',4"-striazine-2,4,6-triyl-tribenzoic acid),a terbium MOFs TbTATB(Tb(TATB)(DMA)(H20)](DMA)3)was designed and synthesized using solvothermal method.Owning to the coordination effect between lewis base functions site of ligands and zinc ions,TbTATB exhibited enhanced fluorescence detection towards zinc ions even in the presence of other interfering ions with high sensitivity.The detection limit reached 10.5 nM.In addition,TbTATB displays excellent biocompatibility,enabling real-time fluorescence imaging in the cell environment,which can be used as potential biomaterials.A terbium MOF material(Me2NH2)2[Tb2(PAPDA)2](H20)6(ZJU-158-Tb)was designed and synthesized based on the organic ligand H4PAPDA(1-(3,5-phenyldicarboxylic acid)-3,5-pyrizole dicarboxylic acid),using solvothermal method.The hydrogen bonding effect between the nitrogen atom in the pyrazole of ligands and uric acid was responsibal for the fluorescence quenching of ZJU-158-Tb by influencing the energy transfer processes from ligands to Tb3+.The high sensitive fluorescence detection of uric acid molecules was realized and the detection limit reached 7 nM.The test papers based on ZJU-158-Tb were prepared by dispensing the suspention of finely grounded ZJU-158-Tb in ethanol onto the tailoring filter papers.The color change of test papers in artificial urine and serum could quickly determine whether the uric acid contents were in abnormal levels.