Based On The Synthesis, Structure And Nature Of Inter-bit Dual-functionalized Aromatic Ligands Of The Metal - Organic Framework Materials

Metal-organic frameworks (MOFs) are a class of compounds with infinite periodic network structures which are constructed by small organic ligands and metal ions or clusters through self-assemble process. It is more controllable in pore size and shape and the synthesis condition is mild, compared with traditional inorganic frameworks. Diversified novel MOFs have been obtained by adjusting ratio of metal to ligand, templates, solvents and synthesis methods according to crystal engineering.The work of this thesis focuses on the preparation of metal organic frameworks based on isophthalic acid derivative which have turnings in their structures. We successfully obtained 6 novel coordination polymers in different reaction conditions. X-ray single-crystal diffraction, infrared spectroscopy (IR), elemental analysis (EA) and thermo gravimetric analysis (TGA) were performed. The gas storage was carried out on some of the novel MOFs. There are mainly three parts in this thesis:First, we synthesized two derivatives of isophthalic acid (m-H2bdc), 5-(pyrrolidin-1-yl) isophthalic (H2pybdc) or 5-(piperidin-1-yl) isophthalic (H2pibdc). Two three-dimensional MOFs were obtained based on them by hydrothermal reaction with metal salts Zn (Ⅱ):{Zn (pybdc)}n(YM-1),{Zn (pibdc)}n(YM-2). It is revealed by single-crystal X-ray diffraction measurement that YM-1 is a 3D (three-dimensional) supramolecular network with 1D channel, in which there is no guest molecule. In the same way, YM-2 was found out a same topology as YM-1. Based on the measurement above, gas storage of YM-1 was carried out. Finally, we chose different metal, temperature and solvent one by one to find out how these factors influenced the reaction.Second, Based on H2pybdc, using 4-(pyridine-4-yl)-pyridine (bpy) as the auxiliary ligand, a two-dimensional grid-type structure of{[Zn (pybdc) (bpy) (H2O)]-2H2O·0.5CH3OH}n(YM-3) was isolated. The single-crystal X-ray diffraction measurement indicates that it is a two-dimensional grid-type coordination polymer. How do the auxiliary ligands impact the reaction? In order to answer this question, we chose different auxiliary ligands instead of 4-(pyridine-4-yl)-pyridine to build MOFs.Third, we synthesized MOFs based on 3-phosphonobenzoic acid. We chose Zn(Ⅱ) or Cu(Ⅱ) to coordinate with the this ligand and obtained 3 3D complexes: {Zn3(pbc)2·2 (H2O)}n(YM-4),{Zn4(m-pbc)2(OH)2(H2O)3}n(YM-5), {[Cu1.5(mpbc)0.5(H2O)0.5]·1.5H2O}n(YM-6). Single-crystal X-ray diffraction measurement reveals that YM-4 has 1D channel in which guest water molecules arrange in order. YM-5 has 1D channel, but water molecules in its channel all coordinate with Zn (Ⅱ). YM-6 has 3D channels filled with guest water molecules in order; besides, there are very beautiful pattern of flower viewing to ab plane. Their structures have been determined by single crystal X-ray diffraction analyses. What's more, thermo stability of some of them has been tested by thermo gravimetric analysis (TGA).