Design,Synthesis,Fluorescence And Adsorption Properties Of Novel Metal-organic Frameworks

Over the past two decades,metal-organic frameworks（MOFs）have become one of the most intense areas of study for chemists,physicists and materials scientists.MOFs are a class of highly crystalline inorganic-organic hybrid materials formed mainly by the self-assembly of metal or metal clusters with multidentate organic ligands.Compared with the traditional inorganic zeolites and porous carbon materials,the excellent properties of MOFs such as high specific surface area,adjustable pore size,easy to modify the skeleton make them have potential application in the fields of fluorescence sensing,energy storage,gas adsorption and separation,magnetic,catalysis,drug release and so on.In this thesis,two novel ligands have been designed and synthesized by rational strategy.Based on the two ligands,a series of new MOFs has been synthesized via solvothermal reaction with lanthanide ions and copper（II）ions.The structure and properties of the MOFs were characterized in detail.The main results are as follows:1.Lanthanide metal-organic frameworks based on a 1,2,3-triazole-containing tricarboxylic acid ligand for luminescence sensing of metal ions and nitroaromatic compounds: An unsymmetrical 1,2,3-triazole-containing tricarboxylic acid ligand 5-[4-（4-carboxy-phenyl）-[1,2,3]triazol^-1-yl]-isophthalic acid（H₃TAIP）was synthesized through the copper-catalyzed azide alkyne cycloaddition（Cu AAC）reaction.Three novel 3D lanthanide metal-organic frameworks materials were synthesized based on the ligand of H₃TAIP: [Tb（TAIP）（DMF）₂]（1）,[La（TAIP）（DMF）₂]?（DMF）0.5（2）and [Eu（TAIP）（DMF）₂]（3）.Single-crystal X-ray diffraction analyses reveal that these metal-organic frameworks are isostructural.The structures are constructed by bi-nuclear lanthanide metal clusters and TAIP3-ligands and possess flu-3,6-C2/c net with point symbol（4²?6）₂（4⁴?6²?8⁷?10²）.We explore the luminescence properties of the three compounds,which shows that compound 1-3 have luminescent properties and the intensity of compound 1 was significantly higher than that of compound 2 and 3,so compound 1 was used for luminescence sensing of metal ions and nitroaromatic compounds,and we found that it exhibits selective detection of 4-nitrophenol and Fe3+ ions in ethanol solution over other nitroaromatic compounds and metal ions.Compound 1 maybe is a potential chemical fluorescence sensing material.2.Synthesis,structure and gas adsorption properties of a stable microporous Cu-based metal-organic framework assembled from T-shaped pyridyl dicarboxylate ligand: A new T-shaped pyridyl dicarboxylate ligand,4?-（pyridin-4-yl）-[1,1?-biphenyl]-3,5-dicarboxylic acid（H₂PBPD）was successfully synthesized through Suzuki reaction.Similarly,a novel 3D metal-organic frameworks of porous materials [Cu（PBPD）（DMF）₂（H₂O）3]（compound 4）was synthesized via solvothermal reaction with copper（II）nitrate based on H₂ PBPD.Single-crystal X-ray diffraction analysis indicates that compound 4 is a three-dimensional framework showing a new（3,6）-connected topology with point symbol（4²?6）₂（4⁴?6²?8⁶?10³）.Stability test shows that compound 4 keeps its crystal structure after being soaked in several organic solvents for two months or calcined at 250 oC for 30 minutes under air atmosphere.The N2 adsorption at 77 K shows compound 4 is microporous with BET surface area of 1682 m2 g^-1.In addition,compound 4 possesses high adsorption capacities for CH4(45 cm3 g^-1)and CO2(114 cm3 g^-1)under ambient pressure and 273 K,respectively.At last,the test of CO2 cyclic adsorption and regeneration of 4 shows that it has a stable CO2 adsorption capacity and no obvious weight change after ten times,and the structure was not destroyed.