Synthesis、Structures And Properties Of Metal-Organic Frameworks Based On N-containing Carboxylic Ligands

Metal-organic frameworks (MOFs) built by metal ions and organic ligands have attracted a great deal of attention because of their designable structures, contronable functions and potential applications in gas adsorption and separation, opticsl, catalysis, magnetism and biological activity. In this thesis,14 MOFs materials have been constructed based on the different kinds of ligands. Furthermore, we explored the gas sorption and luminescent properties of these materials, and obtained some valuable conclusions. The main contents are as follows:1. Based on the trigonal ligand with flexible structures, 2,4,6-tris-(4-carboxyphenoxy)-1,3,5-triazine (H3tcpt), a novel three-dimensional (3D) porous MOF (YZ-1) and double-layer MOF (YZ-2) have been synthesized and characterized. It was found that the single 3D structure of YZ-1 formed when 2D layers, which constructed by ligands connecting the SBUs (Zn2(COO)3), connected by -OH group alone the axial sites of SBUs. YZ-1 also features good thermal stability and could withstand a certain degree of pH changes from 5 to 12. Furthermore, gas adsorption and separation performance of the two MOFs were studied.2. A new triazole carboxylate ligand, (4,4’-(H-1,2,4-triazol-1-yl) methylene-dibenzoic acid, has been prepared. A series of MOFs with the high free void volume based on the triazole carboxylate ligand which possessing variety of coordination modes have been synthesized and characterized, including two MOFs with "cages", three MOFs with "pillar-layered" structure and a MOF with flexible framework. The effect of auxiliary ligands on the formation of the framework, and properties of MOFs towards gas adsorption were studied.3. Four new different kinds of structural MOFs have been obtained based on 6-(3-pyridyl)isophthalic acid. The structural differences among compounds exhibit the backbone of such mixed N- and O-donor atoms organic ligands can be used to construct diverse dimensional MOFs by adjusting the reaction environment. The photoluminescence properties of compounds were investigated, and exhibit intense fluorescent emissions in the solid state at room temperature.