Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
J Synchrotron Radiat. 2022 Mar 1;29(Pt 2):315-322. doi: 10.1107/S1600577522000200. Epub 2022 Feb 25.
The solution-state interactions of plutonium and berkelium with the octadentate chelator 3,4,3-LI(1,2-HOPO) (343-HOPO) were investigated and characterized by X-ray absorption spectroscopy, which revealed in situ reductive decomposition of the tetravalent species of both actinide metals to yield Pu(III) and Bk(III) coordination complexes. X-ray absorption near-edge structure (XANES) measurements were the first indication of in situ synchrotron redox chemistry as the Pu threshold and white-line position energies for Pu-343-HOPO were in good agreement with known diagnostic Pu(III) species, whereas Bk-343-HOPO results were found to mirror the XANES behavior of Bk(III)-DTPA. Extended X-ray absorption fine structure results revealed An-O bond distances of 2.498 (5) and 2.415 (2) Å for Pu and Bk, respectively, which match well with bond distances obtained for trivalent actinides and 343-HOPO via density functional theory calculations. Pu(III)- and Bk(III)-343-HOPO data also provide initial insight into actinide periodicity as they can be compared with previous results with Am(III)-, Cm(III)-, Cf(III)-, and Es(III)-343-HOPO, which indicate there is likely an increase in 5f covalency and heterogeneity across the actinide series.
镎和锫与八齿配体 3,4,3-LI(1,2-HOPO)（343-HOPO）在溶液状态下的相互作用通过 X 射线吸收光谱进行了研究和表征，结果表明，两种锕系金属的四价物种在现场发生还原分解，生成 Pu(III)和 Bk(III)配位配合物。X 射线吸收近边结构（XANES）测量是现场同步辐射氧化还原化学的第一个迹象，因为 Pu 的阈能和白线位置能量与已知的 Pu(III)物种非常吻合，而 Bk-343-HOPO 的结果与 Bk(III)-DTPA 的 XANES 行为相吻合。扩展 X 射线吸收精细结构结果分别揭示了 Pu 和 Bk 的 An-O 键距离为 2.498(5)和 2.415(2)Å，与通过密度泛函理论计算获得的三价锕系元素和 343-HOPO 的键距离非常吻合。Pu(III)-和 Bk(III)-343-HOPO 数据还为锕系元素周期性提供了初步的见解，因为它们可以与之前的 Am(III)-、Cm(III)-、Cf(III)-和 Es(III)-343-HOPO 结果进行比较，这表明 5f 共价性和锕系元素系列中的异质性可能会增加。
