Deblonde Gauthier J-P, Kelley Morgan P, Su Jing, Batista Enrique R, Yang Ping, Booth Corwin H, Abergel Rebecca J
Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Angew Chem Int Ed Engl. 2018 Apr 16;57(17):4521-4526. doi: 10.1002/anie.201709183. Epub 2018 Mar 14.
The chemistry of trivalent transplutonium ions (Am , Cm , Bk , Cf , Es …) is usually perceived as monotonic and paralleling that of the trivalent lanthanide series. Herein, we present the first extended X-ray absorption fine structure (EXAFS) study performed on a series of aqueous heavy actinide chelates, extending past Cm. The results obtained on diethylenetriaminepentaacetic acid (DTPA) complexes of trivalent Am, Cm, Bk, and Cf show a break to much shorter metal-oxygen nearest-neighbor bond lengths in the case of Cf . Corroborating those results, density functional theory calculations, extended to Es , suggest that the shorter Cf-O and Es-O bonds could arise from the departure of the coordinated water molecule and contraction of the ligand around the metal relative to the other [M DTPA(H O)] (M=Am, Cm, Bk) complexes. Taken together, these experimental and theoretical results demonstrate inhomogeneity within the trivalent transplutonium series that has been insinuated and debated in recent years, and that may also be leveraged for future nuclear waste reprocessing technologies.
三价超钚离子（镅、锔、锫、锎、锿……）的化学性质通常被认为是单调的，并且与三价镧系元素系列相似。在此，我们展示了对一系列超过锔的重锕系元素水相螯合物进行的首次扩展X射线吸收精细结构（EXAFS）研究。在三价镅、锔、锫和锎的二亚乙基三胺五乙酸（DTPA）配合物上获得的结果表明，在锎的情况下，金属 - 氧最近邻键长大幅缩短。与这些结果相佐证的是，扩展到锿的密度泛函理论计算表明，相对于其他[M DTPA(H₂O)]（M = 镅、锔、锫）配合物，较短的锎 - 氧和锿 - 氧键可能是由于配位水分子的离去以及配体围绕金属的收缩所致。综合起来，这些实验和理论结果证明了近年来一直被暗示和争论的三价超钚系列中的不均匀性，并且这种不均匀性也可用于未来的核废料后处理技术。
