| Coordination polymers, as one kind of the new functional materials, have been widely used in the fields of luminescent, gas adsorption, catalysis, magnetism and clean energy because of the diversity of structure, high specific surface, easy preparation and function. In this study, under hydrothermal or solvothermal conditions, aromatic multi-carboxylic acids as major ligands, ligands with nitrogen as auxiliary ligands,37 compounds were prepared by reactions with transition metals and rare earth metals. The effects of the geometry of the carboxylic acids ligands and auxiliary ligands on the structure were investigated. The effects of the synthesis conditions on the final structure of the compounds were also discussed. These as-prepared compounds were characterized by the means of single crystal X-ray diffraction, infrared spectra, elemental analysis, thermal gravimetric analysis and powder X-ray diffraction. In addition, catalytic and luminescence properties of some compounds were also studied. The research works are mainly composed of the following four parts:1. Under hydrothermal or solvothermal conditions,7 novel compounds were obtained by the reactions of 5-ethylpyridine-2,3-dicarboxylicacid (EPDA) with transition metal ions. Compounds 1-3 are isostructural, which are zero dimensional complexes. Without nitric acid in the synthesis system of 1-3, compound 4 was obtained. In the mixed solvent system, compound 5 was obtained, and 5 is one-dimensional chain structure, which shows the property of crystal to crystal transformation. When 4,4’-bpy was used as the auxiliary ligand, compound 6 with one-dimensional structure was obtained. When the bpp is used as the auxiliary ligand, compound 7 was obtained. Compound 7 shows a modest catalytic activity for knoevenagel condensation. Moreover, the luminescence properties of compounds 5 and 7 were also studied.2. Employing semirigid V-shaped ligand, benzophenone-2,4’-dicarbonate (BPDA), and transition metal ions,13 novel compounds were synthesized under hydrothermal or solvothermal conditions. Compound 8 is a 1D chain, and compound 9 is a zero dimensional complex. Compound 10 was synthesized under hydrothermal condition, which possesses the three-dimensional structure with pcu topology, and contains a tetranuclear copper cluster structure unit. Using bix as the auxiliary ligand, two-dimensional compounds 11-15 were obtained. Compounds 11 and 12 are isostructural and bear the wave shaped layer structure. Compound 13 is a chiral compound, the chirality of 13 is derived from two strands of the trihelic chains. Compounds 14 and 15 contain binuclear metal cluster structure unit, but due to the difference in connection mode of bix, they exhibit different two-dimensional structure. By introducing bbi, five isostructural compounds (16-20) were obtained. They all possess rob topology structure and exhibit the excellent thermal stability. Compound 8 shows a good catalytic activity, the 90.45% conversion of styrene and 57.13% selectivity of ethylene oxide as well as the 30.65% selectivity of benzaldehyde were obtained at 80℃ after 8 h. Compounds 11-20 with high thermal stability and Lewis acid site were used to study the catalytic performance for knoevenagel condensations. And the effects of different substrates, temperature and catalyst dosage on the catalytic performance were investigated, they show good catalytic activity.3. By self assembly of 2,4,6-pridine tricarboxylic acid (PTA) and transition metal ions or rare earth ions,10 compounds were obtained. Compounds 21 and 22 possess the same structure. In the mixed solvents system, the two-dimensional compound 23 was synthesized, which contains the binuclear copper cluster structure unit. When introducing KOH into the synthesis system, the heterometallic coordination polymers 24 and 25 were obtained, of which 24 is three-dimensional, while 25 is a two-dimensional structure. Compounds 26 and 27 were obtained by using 4-methyl pyridine as auxiliary ligand. And they were all zero-dimensional complexes. Using rare earth metals as metal sources, compounds 28-30 were synthesized under hydrothermal conditions, these three compounds were isostructural. The catalytic performance of compounds 21,22,28 and 29 with Lewis acid site were studied. For the knoevenagel condensation between ethyl acetate and benzene formaldehyde derivatives, compound 21 exhibit a good catalytic activity, and the 83.07% conversion was obtained at 75℃ after 150 min. Rare earth based coordination polymers 28 and 29 also have the good catalytic activity for the knoevenagel condensation between malononitrile and benzene formaldehyde derivatives, and the conversion can reach 97% at 75℃ after 120 min.4. Under solvothermal conditions, by the reactions of 3,3’,4,4’-biphenyltetracarboxylic acid(BPTC) with the transition metal ions,7 compounds were synthesized. By employing the small terminal ligands py and DMF, compounds 31 and 32 were respectively synthesized, and they are two-dimensional structure with the same topology network. Among, compound 32 is a chiral compound. Three two-dimensional coordination polymers were synthesized by using bpp as auxiliary ligands, and compound 33 has a self-threading structure, while isostructural compounds 34 and 35 bear the parallel interpenetrated stucture. The semirigid bix and flexible bbi are respectively introduced as the auxiliary ligands, compound 36 with one-dimensional structure and compound 37 with three-dimensional structure were synthesized. Compound 36 shows a one-dimensional loop-cage structure, and DMSO plays the template role. The catalytic performances of compounds 31-35 for knoevenagel condensation were investigated. The catalytic results show that the compounds 31-35 all show good catalytic activity with nearly complete conversion at 60℃ after 60 min. |
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