Syntheses, Structures And Properties Of Metal-organic Coordination Polymers Based On Long-Chain Aromaticmulticarboxylate

Recently, under the direction of the crystal engineering, the research about the metal-organic coordination polymers and the supramolecular chemistry has attracted more and more attention. The self-assembly of metal centres and organic ligands through coordination bonds or particularly essential supramolecular interactions such as the hydrogen bonds and theÏ€-Ï€interactions can give birth to structures with novel topology and potential applications such as the gas absorption, molecule catalysis, second-order nonlinear optics, luminescence, semiconductor and magnetism etc.In this thesis, we choose a series of long-chain aromaticmulticarboxylate ligands to react with Zn(NO₃)₂, Cd(NO₃)₂ or Ln(NO₃)₃ under hydrothermal or solvothermal condition, to obtain 12 novel coordination polymers. The measurements in this thesis involve the single-crystal X-ray diffraction, the X-ray power diffraction, the IR measurement, the thermo-gravimetric analysis, the magnetism and fluorescent analysis etc.Three similar 3D (three-dimensional) coordination polymers have been obtained by self-assembly using 3,3',5,5'-azobenzenetetracarboxylicacid(H₄abtc) and transition metal ions M²⁺ (M = Zn, Cd): {Zn₂(abtc)(H₂O)₂]·3H₂O·2DMF}_n(1),{[Cd₂(abtc)(H₂O)(DMA)₂]·(H₂O)·3(DMA)}_n(2) and {Cd₂(abtc)(DMF)₃·3DMF}_n(3). 1 and 2 belong to Monoclinic system, space group P2₁/c; 3 belongs to Tetragonal system, space group P4₃2₁2, which is a chiral space group. All the Secondary building units (SBUs) in three polymers are bridged by abtc^4- ligands in such a way to form 3D porous frameworks.Three coordination polymers have been obtained by self-assembly using 3,4',5-tricarboxylate(H3BPT), 2,2'-bipy or 1,4-bbi secondary ligands and transition metal ions M²⁺ (M = Zn, Cd): {[2,2'-bipy][Zn(HBPT)]·H₂O}_n(4),{[2,2'-bipy][Cd(HBPT)]·2H₂O}_n(5) and {[1,4-bbi][Cd₃(BPT)₂(H₂O)]·5H₂O}_n(6). 4 is a 1-dimensional zigzag-shaped ribbon; 5 is a 1-dimensional ladder-shaped chain; 6 is a 2-dimensional layer structure.Five coordination polymers have been obtained by self-assembly using H3BPT and lanthanide metal ions: {Ln(BPT)(H₂O)(DMF)·3H₂O}_n (Ln = Nd, Sm, Eu, Gd, Tb, 7-11). These polymers are isostructural and belong to Monoclinic system, C2/c space group. They adopt a [Ln₂(η²-CO₂)₂(μ²-CO₂)₂] units as their secondery building units (SBUs) to construct 3D framworks, the SBUs are linked together by BPT^3- ligands. The study of solid-state excitation-emission spectroscopy at room temperature suggest that these polymers could find applications as potential fluorescent porous materials. The magnetism of these polymers have also been investigated.We synthesis a new long-chain aromaticmulticarboxylate ligand(H₄PBEC), which contains C≡C bonds. A novel microporous coordination polymer {[Cu₂(PBEC)(H₂O)₂]·2(H₂O)·(DMA)}_n(12) have been prepared via solvothermal reaction using H₄PBEC and Cu(NO₃)₂. The X-ray structure analysis reveals that 12 belongs to Rhombohedral system, R-3 space group. Dinuclear Cu(â…¡) cluster forms the well-known Cu₂(CO₄)(H₂O)₂ paddle-wheel units, these units are inked together by PBEC4- ligands to construct a 3D porous framwork. The luminescence and adsorption properties of 12 have been investigated. The result of adsorption/desorption experiments shows that 12 has high N₂ and H₂ adsorption properties.