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Title: Complexation of Curium(III) with DTPA at 10–70 °C: Comparison with Eu(III)–DTPA in Thermodynamics, Luminescence, and Coordination Modes

Journal Article · · Inorganic Chemistry
DOI:https://doi.org/10.1021/ic5016934· OSTI ID:1182218
 [1];  [2];  [3];  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Stanford Univ., CA (United States). Stanford Research Computing Center
  3. Idaho National Lab. (INL), Idaho Falls, ID (United States)

Separation of trivalent actinides (An(III)) from trivalent lanthanides (Ln(III)) is a challenging task because of their nearly identical chemical properties. Diethylenetriaminepentaacetate (DTPA), a key reagent used in the TALSPEAK process that effectively separates An(III) from Ln(III), is believed to play a critical role in the An(III)/Ln(III) separation. However, the underlying principles for the separation based on the difference in the complexation of DTPA with An(III) and Ln(III) remain unclear. In this work, the complexation of DTPA with Cm(III) at 10-70 ºC was investigated by spectrophotometry, luminescence spectroscopy, and microcalorimetry, in conjunction with computational methods. The binding strength, the enthalpy of complexation, the coordination modes, and the luminescence properties are compared between the Cm(III)-DTPA and Eu(III)-DTPA systems. The experimental and computational data have demonstrated that the difference between Cm(III) and Eu(III) in the binding strength with DTPA can be attributed to the stronger covalence bonding between Cm(III) and the nitrogen donors of DTPA.

Research Organization:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Organization:
USDOE Office of Nuclear Energy (NE)
DOE Contract Number:
AC07-05ID14517
OSTI ID:
1182218
Report Number(s):
INL/JOU-14-33410; TRN: US1500193
Journal Information:
Inorganic Chemistry, Vol. 54, Issue 4; ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English