Syntheses, Crystal Structures And Properties Of Coordination Polymers Constructed From 2, 2'-biimidazole And Its Derivatives

The construction of novel coordination polymers has become a subject that attracts intense attention in the field of supramolecular chemistry and crystal engineering because of their diversity structures and promising applications in catalysis, nonlinear optics, luminescent materials, porous materials and microelectronics.Coordination polymers may easily be affected by various factors, such as the environment of the metals, the structure of the organic-ligands, the molar ratio of materials, the appropriate reaction conditions, which may have a great effect on the ultimate structures. Organic-ligands play an important role in the construction of the coordination polymers, therefore, more and more people devote to construct novel coordination polymers with appropriately designed organic ligands. N- or O-donor molecules received much attention in the field of coordination chemistry and the reason for this might be that nitrogen or oxygen, which is sp2-hybridized and is embedded in an aromatic or any other unsaturated system, is an excellent donor for the coordination to metal ions. At present, chemists have realized the construction of coordination polymers using two different kinds of organic-ligands with one metal ion or one organic-ligand assemblied with two different metals. Furthermore, the strategies for the synthesis of the materials are various, such as solvent volatilization, room temperature diffusion, hydrothermal /solvent thermal, pillared method and so on. At the present time the synthesized coordination polymers have took on abundant structure topologies, such as one-dimensional linear chain, Zigzag chain, helical chain, rotaxane type, tow-dimensional honeycomb type, stick and wall type, graphite type, square lattice type, three-dimensional diamond type and primitive cubic types and so on.The aim of this thesis is the construction of new coordination compounds from three organic ligands (H2biim, L1, L2) combined with metal ions and phenyl dicarboxylate ligands. The study on synthetic conditions and rules for these new compounds, topological analyses, and the exploration of relationships between structures and properties for these new compounds are also carried out.Nine new coordination compounds have been synthesized under hydrothermal conditions and structurally characterized by elemental analyses and single crystal X-ray diffractions. The fluorescent properties of these compounds that constructed from d10 metal ions have been studied.1. Two new compounds based on 2,2'-biimidazole (H₂biim) and coligands have been synthesized under hydrothermal conditions and structurally characterized by X-ray diffraction analysis, which exhibiting 3D diamond topology [Cd₂(Hbiim)₄]n 1, 3D supramolecular structure [Cd(H₂biim)₂(C₄O₄H₂)]n 2. The study on the coordination modes of the ligands and the effect of coligand on the ultimate structures are also carried out.2. Five frameworks with 3D self-penetrating framework [Zn2(L1)(m-bdc)2] 3, 2D framework {[Cd(L1)(m-bdc)]H2O}n 4, 2D structure with (4,4) grid [Co(L1)0.5(m-bdc)(H2O)]n 5, 3D (3,8)-connected network [Zn5(L1)2(p-bdc)5(H2O)]n 6 and 3D network with distortedα-Po topology [Zn5(L1)2(p-bdc)5(H2O)]n 7 have been synthesized under hydrothermal conditions based on L1 ligand and benzendicarboxylate acid. The coordination modes of the ligands and the effect cause from different metal ions and coligands on the ultimate structures have been studied. We also discussed the fluorescent properties based on d10 metal ions.3. Two 3D frameworks with distortedα-Po topologies 8 and 9 have been constructed from L2 ligands and the coexistence of the coligands. The coordination modes of the ligands and the effect cause from different coligands on the ultimate structures have been studied. We also discussed the fluorescent properties of the two compounds.