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Title: Exploring Soft Donor Character of the N-2-Pyrazinylmethyl Group by Coordinating Trivalent Actinides and Lanthanides Using Aminopolycarboxylates

Abstract

The trivalent f-element coordination chemistry of a novel aminopolycarboxylate complexant was investigated. The novel reagent is an octadentate complexant, that resembles DTPA (diethylenetriamine-N,N,N',N'',N''-pentaacetic acid), but a single N-acetate pendant arm was substituted with a N-2-pyrazinylmethyl functional group. Thermodynamic studies of ligand protonation, and trivalent lanthanides, americium and curium complexation by N-2-pyrazinylmethyl-diethylenetriamine-N,N',N'',N''-tetraacetic acid, DTTA-PzM, emphasize a strong electron-withdrawing influence of the N-2-pyrazinylmethyl group. Specifically, DTTA-PzM is more acidic, when compared to a N-2-pyridinylmethyl-substituted structural equivalent, DTTA-PyM, with a substantial lowering of pK7, corresponding to the protonation of a second aliphatic amine site. The participation of the pyrizyl nitrogen in the metal ion coordination sphere is evident from the fluorescence lifetime decay measurements of metal hydration, and the interpretation of the stability constants for ML and MHL(aq) complexes. The overall conditional stability constants for the trivalent f-element complexation by DTTA-PzM complexes decrease, relative to DTTA-PyM, as expected based on the lower basicity of pyrazine in water, relative to pyridine. A replacement of N-2-pyridinylmethyl group with N-2-pyrazinylmethyl, while enhancing the total acidity of DTTA-PzM, also reduces its softness, as manifested by a small lowering of ß101Am/Nd and liquid-liquid separation of trivalent lanthanides from trivalent americium. Despite this the 4f/5f separation is doubled whenmore » DTTA-PzM replaces DTPA as an aqueous complexant in solvent extraction.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [1]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
OSTI Identifier:
1591637
Alternate Identifier(s):
OSTI ID: 1564174
Report Number(s):
INL/JOU-19-55470-Rev000
Journal ID: ISSN 0020-1669
Grant/Contract Number:  
AC07-05ID14517; AC02-05CH11231; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 59; Journal Issue: 1; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; aminopolycarboxylates; actinides; lanthanides; metal chelators; aqueous separations

Citation Formats

Grimes, Travis S., Heathman, Colt R., Jansone-Popova, Santa, Ivanov, Alexander S., Bryantsev, Vyacheslav S., and Zalupski, Peter R. Exploring Soft Donor Character of the N-2-Pyrazinylmethyl Group by Coordinating Trivalent Actinides and Lanthanides Using Aminopolycarboxylates. United States: N. p., 2019. Web. doi:10.1021/acs.inorgchem.9b01427.
Grimes, Travis S., Heathman, Colt R., Jansone-Popova, Santa, Ivanov, Alexander S., Bryantsev, Vyacheslav S., & Zalupski, Peter R. Exploring Soft Donor Character of the N-2-Pyrazinylmethyl Group by Coordinating Trivalent Actinides and Lanthanides Using Aminopolycarboxylates. United States. doi:10.1021/acs.inorgchem.9b01427.
Grimes, Travis S., Heathman, Colt R., Jansone-Popova, Santa, Ivanov, Alexander S., Bryantsev, Vyacheslav S., and Zalupski, Peter R. Tue . "Exploring Soft Donor Character of the N-2-Pyrazinylmethyl Group by Coordinating Trivalent Actinides and Lanthanides Using Aminopolycarboxylates". United States. doi:10.1021/acs.inorgchem.9b01427.
@article{osti_1591637,
title = {Exploring Soft Donor Character of the N-2-Pyrazinylmethyl Group by Coordinating Trivalent Actinides and Lanthanides Using Aminopolycarboxylates},
author = {Grimes, Travis S. and Heathman, Colt R. and Jansone-Popova, Santa and Ivanov, Alexander S. and Bryantsev, Vyacheslav S. and Zalupski, Peter R.},
abstractNote = {The trivalent f-element coordination chemistry of a novel aminopolycarboxylate complexant was investigated. The novel reagent is an octadentate complexant, that resembles DTPA (diethylenetriamine-N,N,N',N'',N''-pentaacetic acid), but a single N-acetate pendant arm was substituted with a N-2-pyrazinylmethyl functional group. Thermodynamic studies of ligand protonation, and trivalent lanthanides, americium and curium complexation by N-2-pyrazinylmethyl-diethylenetriamine-N,N',N'',N''-tetraacetic acid, DTTA-PzM, emphasize a strong electron-withdrawing influence of the N-2-pyrazinylmethyl group. Specifically, DTTA-PzM is more acidic, when compared to a N-2-pyridinylmethyl-substituted structural equivalent, DTTA-PyM, with a substantial lowering of pK7, corresponding to the protonation of a second aliphatic amine site. The participation of the pyrizyl nitrogen in the metal ion coordination sphere is evident from the fluorescence lifetime decay measurements of metal hydration, and the interpretation of the stability constants for ML– and MHL(aq) complexes. The overall conditional stability constants for the trivalent f-element complexation by DTTA-PzM complexes decrease, relative to DTTA-PyM, as expected based on the lower basicity of pyrazine in water, relative to pyridine. A replacement of N-2-pyridinylmethyl group with N-2-pyrazinylmethyl, while enhancing the total acidity of DTTA-PzM, also reduces its softness, as manifested by a small lowering of ß101Am/Nd and liquid-liquid separation of trivalent lanthanides from trivalent americium. Despite this the 4f/5f separation is doubled when DTTA-PzM replaces DTPA as an aqueous complexant in solvent extraction.},
doi = {10.1021/acs.inorgchem.9b01427},
journal = {Inorganic Chemistry},
number = 1,
volume = 59,
place = {United States},
year = {2019},
month = {8}
}

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