Felton Daniel E, Fairley Melissa, Arteaga Ana, Nyman May, LaVerne Jay A, Burns Peter C
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame 46556, Indiana, United States.
Radiation Laboratory, University of Notre Dame, Notre Dame 46556, Indiana, United States.
Inorg Chem. 2022 Aug 1;61(30):11916-11922. doi: 10.1021/acs.inorgchem.2c01657. Epub 2022 Jul 17.
Aqueous solutions of lithium uranyl triperoxide, Li[UO(O)] (LiUT), were irradiated with gamma rays at room temperature and found to form the uranyl peroxide cage cluster, Li[(UO)(O)(OH)] (Li-U). Raman spectroscopy and O labeling were used to identify the Raman-active vibrations of LiUT. With these assignments, the concentration of LiUT was tracked as a function of radiation dose. A discrepancy between monomer removal and cluster formation suggests that the reaction proceeds by the assembly of an intermediate. Non-negative matrix factorization was used to separate Raman spectra into components and resulted in the identification of a unique intermediate species. Much of the conversion appears to be driven by water radiolysis products, particularly the hydroxyl radical. This differs from the O-labeled copper-catalyzed formation of U, which progresses at a steady rate with no observation of intermediates. Li-U in solution decomposes at high radiation doses resulting in a solid insoluble product similar to Na-compreignacite, Na(UO)O(OH)·7HO, which contains uranyl oxyhydroxy sheets.
在室温下，用伽马射线辐照三过氧化铀酰锂（Li[UO(O)]，简称LiUT）的水溶液，发现形成了过氧化铀酰笼状簇合物Li[(UO)(O)(OH)]（Li-U）。利用拉曼光谱和氧标记来识别LiUT的拉曼活性振动。通过这些归属，跟踪LiUT的浓度随辐射剂量的变化。单体去除与簇合物形成之间的差异表明反应是通过中间体的组装进行的。使用非负矩阵分解将拉曼光谱分离成组分，从而鉴定出一种独特的中间物种。大部分转化似乎是由水的辐射分解产物驱动的，特别是羟基自由基。这与氧标记的铜催化形成U的情况不同，后者以稳定的速率进行，未观察到中间体。溶液中的Li-U在高辐射剂量下分解，产生一种类似于钠综合水铀矿（Na(UO)O(OH)·7HO）的固体不溶产物，该产物含有铀酰羟基片层。
