Uranyl Organic Coordination Compounds Based On Carboxylic Acid Ligans Containing Olefin Or Azo Groups

Nuclear energy with the advantage of high efficiency and cleanliness has good prospects in our society.While,plenty of radioactive solid wastes generated in the process,which is also an urgent problem to be solved.Uranium as a key object of nuclear waste,has received widespread attention,and the study of uranium element coordination chemistry,can make us have a further understanding of the behavior of uranium element,thus providing scientific guidance in spent fuel reprocessing and recycling,finally promoting the development of nuclear energy.Based on our extensive efforts in uranyl coordination compound architectures,this thesis is focused on property and functionalization of the uranyl coordination compounds.We employ uranyl ion(UO₂²⁺)as the metal center,functional single carboxylic acid containing vinyl or azo group as ligands to synthesize uranyl coordination polymer with potential application properties.The main work content is as follows:?1?We prepared five uranyl organic complexes using?E?-methyl 3-?pyridin-4-yl?acrylate or?E?-methyl 3-?pyridin-3-yl?acrylate as main ligand,1,10-phenanthroline as auxiliary ligand,through hydrothermal reaction.Due to the conjugated structure of aromatic ring and vinyl groups in ligands,there exit abundant?-?interactions.In addition,these compounds also contain a lot of hydrogen bonds of N-H…O,which also enhance binding force of the complexes molecular,and are conducive to forming Pseudothree-dimensional structure.Comparing the five complexe structures,we selected compound 1 and 3 to carry out the photoinduced experiment,and the results showed that compound 1 and 3 have the characteristic of fluorescence attenuation after UV lamp irradiation.The mechanism may be due to the slight rotation of the pyridine ring,binding with carbon carbon double bond,finally resulting in the increased degree of nonradiative relaxation of excited states.The exploration of this kind of uranyl complexes provides some references for the application in optical materials.?2?We utilized 3,3?,5,5?-azobenzenetetracarboxylic acid?H₄abtc?to reaction with uranyl nitrate hexahydrate UO₂?NO₃?₂·6H₂O through solvothermal method,and obtained a 3 D uranyl coordination compound framework with plentiful dimethylamine[?CH₃?₂NH₂]⁺ions existing in the open channels,which can serve as the ion exchange sites.The experimental results show that this material exhibits excellent adsorption performance on Eu³⁺ions,the analogue of Am?III?,and the mechanism of ion exchange is exactly explained by ¹H-NMR spectrum.