| In recent years, the metal-organic frameworks(MOFs), as a kind of hybrid materials with inorganic and organic characteristics, have attracted considerable attention due to their prospective applications in the areas such as gas storage and separation, catalysis and ion exchange. The MOFs constructed from the mixed ligands of nitrogen heterocyclic ligand and carboxylic acid or from the ligand of the aromatic carboxylic acid with nitrogen heterocyclic group generally present some unique topology structure and properties.In this thesis, three metal-organic frameworks of {[Cd(2-NO2-1,4-BDC)(BPYETE)](DMF)}n(1)(2-NO2-1,4-BDC: Nitroterephthalic acid; BPYETE:1,2-Bis(4-pyridyl)ethyne), {[Zn(2-NH2-1,4-BDC)(BPYETE)](DMF)}n(2)(2-NH2-1,4-BDC:2-Aminoterephthalic acid) and {[Zn(1,4-BDC)(BPYETE)](DMF)}n(3)(1,4-BDC : terephthalic acid) have been obtained by reaction of aromatic acid containing the nitro or amino group, 1,2-Bis(4-pyridyl) acetylene and metal salts. In addition, an organic ligand of 4-(benzimidazole-1-yl) benzoic acid has been synthesized. Five metal-organic frameworks of {[Zn3(bmzbc)6]·(solvent)]}n(4)(bmzbc: 4-(benzimidazole-1-yl) benzoato), {[Cu(bmzbc)2]·(DMF)2(H2O)4}n(5),{[Cd(bmzbc)2]·(DMF)2(H2O)4 }n(6) and{[Zn(bmzbc)2]}n(7), {[Pb(bmzbc)2]}n(8)based on the 4-(benzimidazole-1-yl) benzoate ligand and zinc(II), copper ion(II),cadmium(II) ion, or lead(II) ion have been synthesized. All compounds were characterized by single-crystal X-ray diffraction, IR spectra and thermogravimetric analysis. The gas adsorption of compound 1, 2 and 4 has been tested. The fluorescence properties of copound of 3, 4, 6, 7 and 8 have also been studied.Four chapters are presented in this thesis.The first chapter has mainly reviewed the concept, synthesis methods, the applications of the metal-organic frameworks, the latest research progress on metal-organic frameworks which were built with nitrogen heterocyclic ligands and carboxylic acid ligand.The second chapter described the syntheses and structures of the threemetal-organic frameworks 1, 2 and 3, which were constructed from 1,2-Bis(4-pyridyl)acetylene and aromatic carboxylic acid. We found that the three MOFs have similar two-fold interpenetrated three dimentional structure, in which the aromatic acid link the the mtal ions to form a two-dimensional layer that further linked by1,2-bis(4-pyridyl) acetylene to generate a three-dimentional network with one-dimensional channal which was occupied by DMF molecules. We try to displace the DMF molecules by dipping the compounds 1-3 into the acetone solution, methanol solution and chloroform solution, and only in MOFs 1, the DMF solvents have been partially exchanged. The gas sorption properties of the MOFs 1 and 2 on N2 and CO2 have been extensively studied. The compound 1 showed certain adsorption capacity on N2 and CO2, but the compound 3 almost displays no adsorption on N2 and CO2, which may be due to the DMF molecules in the pores have not been completely removed.Fourthermore, the fluorescence property of 2 has been investigated..The third chapter described the syntheses and structures of a organic ligand of4-(benzimidazole-1-yl) benzoic acid and five metal-organic frameworks constructed from the 4-(benzimidazole-1-yl) benzoate ligand. The MOFs 4 features a two-fold interpenetrated three dimentional structure with α-quartz topology. Interestingly, the two interpenetrated nets has opposite chirality. The gas sorption properties of the MOFs 4 on N2 and CO2 have been extensively studied. The compound 4 do not adsorb N2, and adsorb little CO2, which may be due to the shrinkage of the skeleton of 4 or no effective adsorption site for the gas molecules. The compound 3, 4, 5, 6, 7 and 8 all feature two-dimensional structure, and the fluorescence properties of these compounds have also been studied in detail.The last chapter is the conclusion and an outlook on this thesis. |
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