Controlling the Reduction of Chelated Uranyl to Stable Tetravalent Uranium Coordination Complexes in Aqueous Solution

The solution-state interactions between octadentate hydroxypyridinone (HOPO) and catecholamide (CAM) chelating ligands and uranium were investigated and characterized by UV-visible spectrophotometry and X-ray absorption spectroscopy (XAS), as well as electrochemically via spectroelectrochemistry (SE...

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Bibliographic Details
Published in:Inorganic chemistry 2020-12, Vol.60 (2)
Main Authors: Carter, Korey P., Smith, Kurt F., Tratnjek, Toni, Deblonde, Gauthier J. -P., Moreau, Liane M., Rees, Julian A., Booth, Corwin H., Abergel, Rebecca J.
Format: Article
Language:English
Subjects:
cations
extended x-ray absorption fine structure
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ligands
nuclear chemistry
radiation chemistry
radiochemistry
redox reactions
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Summary:The solution-state interactions between octadentate hydroxypyridinone (HOPO) and catecholamide (CAM) chelating ligands and uranium were investigated and characterized by UV-visible spectrophotometry and X-ray absorption spectroscopy (XAS), as well as electrochemically via spectroelectrochemistry (SEC) and cyclic voltammetry (CV) measurements. Depending on the selected chelator, we demonstrate the controlled ability to bind and stabilize UIV, generating with 3,4,3-LI(1,2-HOPO), a tetravalent uranium complex that is practically inert toward oxidation or hydrolysis in acidic, aqueous solution. At physiological pH values, we are also able to bind and stabilize UIV to a lesser extent, as evidenced by the mix of UIV and UVI complexes observed via XAS. Finally, CV and SEC measurements confirmed that the UIV complex formed with 3,4,3-LI(1,2-HOPO) is redox inert in acidic media, and UVI ions can be reduced, likely proceeding via a two-electron reduction process.
ISSN:0020-1669