Research Of Metal-Organic Frameworks Based On Penta-carboxylate Ligand

Recently metal-organic frameworks (MOFs) have attracted considerable interest due to their versatile structural topologies as well as potential applications in gas adsorption and separation, catalysis, drug delivery, magnetism and luminescence. Aromatic polycarboxylates are the most commonly used ligands for constructing MOFs due to their rich coordination modes and structural rigidity. However, pentacarboxylates ligands, especially those with big size, have not been used as frequently probably because of their low symmetry and difficulty in synthesis. Meanwhile, number of (5,5)-connected nets are limited because of their low symmetry. In this dissertation, three new penta-carboxylates ligands and their corresponding MOFs were designed and synthesized. Details are presented as below:1. Three new penta-carboxylates ligands, H5La, H5Lb and H5Lc (H5La5,5’-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino) diisophthalic acid; H5Lb=2,5-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino) diterephthalic acid; H5Lc=5,5’-(6-(3-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino) diisophthalic acid) were designed, synthesized and characterized.2. Ten new MOFs were prepared through the reactions of the ligands and transition metal ions. Of these seven compounds (1-7) are based on H5La.1-6exhibit3D (5,5)-connected framework and the corresponding point symbol are44.66(1-4),(46.64)(46.64)(5),46.64or bnn (6) respectively.7displays a3D (4,8)-connected neutral framework with (46)2(412.612.84)(flu) topology. Two (8and9) are based on H5Lb.8is a3D (4,4)-connected zeolite-type framework with42.63.8(abw) topology.9bears a2D (4,8)-net structure. One (10) is based on H5Lc.10has a (4,4,6)-connected framework and is characterized by its near-spherical large cage. Besides10also has a new topology:(43.63)2(44.67.84)2(46). The compounds were further characterized by TGA, N2sorption, magnetic and luminescent analysis.3. The relationship between configuration, coordination mode of ligands and the structures, properties of MOFs were summarized, which would be helpful for the future research.