Synthesis, Structure And Property Characterization Of Uranium Coordination Polymers

Synthesis of the coordination polymers is a hotspot of crystal engineering, investigating coordination polymers can not only deepen the understanding of crystal theory, but also prepare lots of novel materials. These materials may exhibit find applications in the fields of gas sorption and storage, optical, electrical, magnetic properties, and play important roles in catalysis, etc.Compared with other metal-coordination polymers, the actinide polymers(the uranyl complexes as the representative) as a special class complex, Nowadays, as the increasing scareity of energy has become extremely urgent. By studying the actinide coordination complex can help to understand the physical and chemical properties of actinide elements. In addition, by studying the coordination behaviors of actinides with organic or inorganic ligands, we can acquire basic principles to design extraction agent. Furthermore, to further understand the nature of nuclide migration has guiding role and help realization reuse the nuelear waste.In this work, we used the uranium as central metal ion, which is representative of actinides. We synthesized several uranyl coordination polymers under hydrothermal conditions and research on the diversity of actinide coordination polymers. Meanwhile we make further study on the related properties. Specific works are listed as follows:(1) Under the hydrothermal conditions, two novel uranyl coordination polymers were synthesized using uranyl nitrate, 3,3’,4,4’-benzophenonetracarboxylic acid(H4bptc) dianhydride and two different auxiliary or templating N-containing ligands. TGA, IR spectra, PXRD and solid fluorescence spectrum are measured. The results of solid fluorescence spectrum revealed that the two complexes exhibit typical uranium five-peak fluorescence. In addition, we used DFT calculations to analyze the bonding natures of the two complexes.(2) Hydrothermal method was successfully used to synthesis four complexes. In the experiment, we used 2,2’-biquinoline-4,4’-dicarboxylic acid(H2bqdc) as the main ligand, three different auxiliary N-containing ligand. The structures of these four complexes are determined by X-ray single crystal diffraction technology, and measured by TGA, IR spectra, PXRD and solid fluorescence spectrum. Significantly, the uranyl complexes didn’t show the uranium characteristic fluorescence peak.(3) Three uranyl complexes have been synthesized with the benzene-1,4-dicarboxylate(BDC) and two different N--containing ligand. The results show that the p H and the different types of N-containing auxiliary ligands are play important roles in the construction of the diversity uranyl complexes. In addition, the complexes have been characterized by means of TGA, IR spectra, PXRD and solid fluorescence spectrum.