Spectroscopic and Computational Characterization of Diethylenetriaminepentaacetic Acid/Transplutonium Chelates: Evidencing Heterogeneity in the Heavy Actinide(III) Series

Gauthier J-P Deblonde; Morgan P Kelley; Jing Su; Enrique R Batista; Ping Yang; Corwin H Booth; Rebecca J Abergel

doi:10.1002/anie.201709183

Spectroscopic and Computational Characterization of Diethylenetriaminepentaacetic Acid/Transplutonium Chelates: Evidencing Heterogeneity in the Heavy Actinide(III) Series

Angew Chem Int Ed Engl. 2018 Apr 16;57(17):4521-4526. doi: 10.1002/anie.201709183. Epub 2018 Mar 14.

Authors

Gauthier J-P Deblonde¹, Morgan P Kelley², Jing Su², Enrique R Batista², Ping Yang², Corwin H Booth¹, Rebecca J Abergel^{1

3}

Affiliations

¹ Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
² Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
³ Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.

PMID: 29473263
DOI: 10.1002/anie.201709183

Abstract

The chemistry of trivalent transplutonium ions (Am³⁺ , Cm³⁺ , Bk³⁺ , Cf³⁺ , Es³⁺ …) 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 Cf³⁺ . Corroborating those results, density functional theory calculations, extended to Es³⁺ , 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^III DTPA(H₂ O)]^2- (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.

Keywords: EXAFS spectroscopy; actinides; berkelium; californium; chelates.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.