Uranyl Phosphonate Coordination Compounds: Synthesis,Characterization And Fluorescence

Forty years after the reform and opening up,China's economy has developed rapidly.At the same time,the consumption of traditional fossil energy has been increasing,but the environmental problems that have followed have become increasingly prominent.The development of clean energy has become an inevitable choice in line with the trend of the times.Among many new energy sources,nuclear energy has been rapidly developed as a clean and reliable energy source,and the economic and social benefits produced by it are also very obvious.However,the by-products generated during the nuclear fuel cycle process will also cause some pressure on the environment.As a part of the by-products,depleted uranium has become a research hotspot for scientists in various countries.At present,due to the special physical properties of uranium,the utilization of depleted uranium is mainly limited to military aspects,such as armor-piercing cores and protective armor.And as a peaceful country,how does China carry out the peaceful use of depleted uranium? This project hopes to use the intrinsic fluorescence of uranyl units to construct metal-organic framework materials based on uranyl and phosphonate ligands and apply them to temperature probe and ultraviolet detection,so as to achieve the peaceful use of depleted uranium.It also provides a possible way to solve the problem of depleted uranium.In this project,six uranyl-based phosphonate framework materials were synthesized by hydrothermal method and ionothermal method.Their crystal structures were obtained by single crystal X-ray diffraction technology,and their purity was confirmed by means of powder X-ray diffraction.Its Ultraviolet-visible(UV-vis)absorption spectrum,Fluorescence spectrum(Fluorescence),Infrared-Raman spectrum(IR-Raman)and Thermogravimetric(TG)are used to characterize compounds.Some of the compounds are used for temperature detection.The specific research is as follows:1.A supramolecular compound(UPC-1)with one-dimensional uranyl phosphonate structure was synthesized by a hydrothermal method.Its temperature-varying fluorescence spectrum shows a negative correlation between fluorescence intensity and temperature change.The lower the temperature,the higher the intensity.It has a good linear relationship in the low temperature range,and has potential applications for temperature probe.2.A three-dimensional uranyl phosphonate coordination compound(UPC-2)was synthesized by hydrothermal method.When the temperature rises from 98 K to 298 K,UPC-2achieves the conversion from single crystal to single crystal,accompanied by changes in the lattice water and benzene rings from ordered to disordered,and a negative correlation between fluorescence and temperature.It has potential application of temperature detection.3.Four three-dimensional uranyl phosphonate coordination compounds(UPC-3,4,5 and6)were synthesized using ionothermal method and the "Sterically Hindered Phosphonate Ligand" strategy.The validity of this strategy in constructing three-dimensional porous uranyl phosphonate framework materials was verified,which provided a new path for the further development of this type of new functional materials.