Study On The Synthesis And Performance Of MOFs Based On Thiophene Carboxylic Acid Ligands

Luminescent metal-organic frameworks are a kind of multiparous material with rich luminescent sites and excellent luminescent properties.It has great application prospects in fluorescence recognition of environmental pollutants,monitoring of temperature and regulation of white light.In addition,the transitional metal-organic framework materials not only used as sensors,but also have outstanding advantages in protecting and sensitizing the lanthanide metal ions luminescence due to their high porosity,large specific surface area and functional group diversity.At the same time,different luminescence properties before and after sensitization of MOFs are used to distinguish and identify environmental pollutants.?1?In this paper,we selected 2,5-thiophenedicarboxylic acid?L₁?as the organic ligand,with Eu???and Tb???as metal ions to synthesize a series of lanthanide metal organic frameworks Eu_xTb_1-x-MOFs?x=0.5,0.067,0.05,0.01,0.00833,0.00667,0.005?;combined metal ion of Cd???and 5-??4-carboxyphenyl?formylamino?thiophe-ne-2-carboxylic acid?L₂?to obtain a transition metal organic framework Cd₄?L?₄·4H₂O?Cd-MOF?by solvothermal method.MOFs were analyzed and characterized by powder X-ray diffraction?PXRD?,infrared spectroscopy?FT-IR?and other methods,and their photophysical properties were also measured by ultraviolet-visible diffuse reflectance spectroscopy?DRS?,fluorescence spectrum?PL?and so on.X-ray single crystal diffraction show that Cd-MOF has stable 3D supramolecular network structures.?2?Studied a series of lanthanide metal organic frameworks Eu_xTb_1-x-MOFs?x=0.5,0.067,0.05,0.01,0.00833,0.00667,0.005?luminescence adjustment process,the results show that the white light-emitting material Eu_0.00667Tb_0.99333-MOF can be and explored its sensing of phenolic compounds and monitoring of physiological temperature?288-353 K?.The results show that Eu_0.00667Tb_0.99333-MOF can selectively recognize?-naphthol and excellent monitoring effect in the temperature in the physiological range.In summary,Eu_0.00667Tb_0.99333-MOF as a white light emitting material has broad development prospects in the detection of pollutants and physiological temperature.?3?The fluorescence performances of Cd-MOF on sensing of metal ions,anions,nitroaromatic compounds and phenolic compounds were studied.Besides,Eu³⁺@Cd-MOF was obtained by sensitizing Eu³⁺luminescence in Cd-MOF package.The fluorescence detection of metal ions and anions was also studied.The results show that Cd-MOF as a sensor can selectively identify environmental pollutants such as Fe???,Cr???(Cr₂O₇^2-and CrO₄^2-)and nitroaniline compounds and nitrophenol compounds,but it is impossible to distinguish between Fe???,Pb???,and Cr??? different detection effects on Fe???,Pb???and Cr???in the water environment.Therefore,combine the different results of Cd-MOF and Eu³⁺@Cd-MOF on sensing of Fe???,Pb???and Cr???can distinguish Fe???,Pb???and Cr???in the same aqueous solution,this method provides a new idea for MOFs materials to distinguish environmental pollution in the future.