Synthesis, Structure And Properties Of Porous Coordination Polymers Based On Tripodal Carboxylate Ligand

Recently, intensive research has been devoted to the design and construction of porous metal-organic frameworks, in part due to their intriguing architectures, novel framework topologies, as well as potential applications in catalysis, gas storage, molecular recognition, ion exchange, separation, magnetic materials, NLO materials, luminescence and nonlinear optics and so on. It has received rather considerable attention in the field of chemistry and material. A metal-organic framework consists of metal ion or metal cluster joined by organic bridging ligands to give a well-defined periodic structure. So, it is a key step to choose proper organic ligands. Previous research has shown that the symmetrical organic ligands are easier to form porous metal-organic frameworks. For this reason, we selected two tripodal organic ligands:4,4’,4"-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))-tribenzoic acid (H3BBC) and benzene-1,3,5-tribenzoic acid (H3BTB). In this paper, three porous metal-organic frameworks have been synthesized by solvothermal synthetic techniques based on transition metal ions and linear N-donor ligands or linear carboxylate ligands. These coordination polymers were characterized by X-ray single-crystal diffraction, XRD, elemental analysis, thermogravimetric analysis and infrared spectra. The circular dichroism, fluorescence properties and photocatalysis degradation of partial compounds have also studied and discussed. This paper includes the following four chapters:In the first chapter, we introduced briefly the basic conception of coordination polymer and the recent research results in the field. On the other hand, we systematically introduce the structural characteristic and application of some typical compounds and the research progress made in this paper.In the second chapter, The reaction of zinc nitrate and H3BBC under solvothermal condition leads to the generation porous coordination polymers [Zn(BBC)(H2O)2](Me2NH2)·12DMF (1). The BBC ligands connects Zn2(COO)3SBUs to generate a2D layer with (6,3) topological net based on Zn2(COO)3and BBC ligands as a node. The adjacent2D layers are stacked parallelly by hydrogen bond to form a3D porous supramolecular framework with hexagonal channels. When NH2-H2BDC is present in the reacting mixture, it acts as a pillar, generating a porous3D network [Zn2(BBC)(NH2-BDC)](Me2NH2)·10DMF (2).2exhibits an interesting3-fold interpenetrating (3,5)-connected network consisting of large1-D hexagonal channels. The resulting crystals of1and2were not racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using the solid circular dichroism (CD) spectra based on large crystals from one crystallization. Two compounds exhibit strong photoluminescence in the solid state at room temperature.In the third chapter, A Co(II)-based porous metal-organic framework,[Co6(btb)4(4,4’-bipy)3(DMA)44](3)(btb=benzene-1,3,5-tribenzoate,4,4’-bipy4,4’-bipyridine) has been synthesized by solvothermal method.3is a3D neutral framework featuring two kind porous channels constructed by Co2(COO)4paddle-wheel and btb tritopic linkers. The photocatalytic decolorization of methylene blue, methyl orange and crystal violet dye in aqueous solution using a novel photocatalyst was investigated under UV-vis light.In the fourth chapter, we have summarized the structures and properties of the three porous metal-organic frameworks.