Computational tools for calculating log β values of geochemically relevant uranium organometallic complexes
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Published version
Author(s)
Kirby, M
Simperler, Alexandra
Krevor, Samuel
Weiss, Dominik
Sonnenberg, Jason
Type
Journal Article
Abstract
Uranium (UVI) interacts with organic ligands, subsequently controlling its aqueous chemistry. It is therefore imperative to assess the binding ability of natural organic molecules. We evidence that density functional theory (DFT) can be used as a practical protocol for predicting the stability of UVI organic ligand complexes, allowing for the development of a relative stability series for organic complexes with limited experimental data. Solvation methods and DFT settings were benchmarked to suggest a suitable off-the-shelf solution. The results indicate that the IEFPCM solvation method should be employed. A mixed solvation approach improves the accuracy of the calculated stability constant (log β); however, the calculated log β are approximately five times more favorable than experimental data. Different basis sets, functionals, and effective core potentials were tested to check that there were no major changes in molecular geometries and ΔrG. The recommended method employed is the B3LYP functional, aug-cc-pVDZ basis set for ligands, MDF60 ECP and basis set for UVI, and the IEFPCM solvation model. Using the fitting approach employed in the literature with these updated DFT settings allows fitting of 1:1 UVI complexes with root-mean-square deviation of 1.38 log β units. Fitting multiple bound carboxylate ligands indicates a second, separate fitting for 1:2 and 1:3 complexes.
Date Issued
2018-09-04
Date Acceptance
2018-09-04
Citation
Journal of Physical Chemistry A, 2018, 122 (40), pp.8007-8019
ISSN
1089-5639
Publisher
American Chemical Society
Start Page
8007
End Page
8019
Journal / Book Title
Journal of Physical Chemistry A
Volume
122
Issue
40
Copyright Statement
© 2018 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY)
License (https://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
License (https://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
License URL
Sponsor
Natural Environment Research Council (NERC)
Grant Number
NE/L000660/1
Subjects
0307 Theoretical And Computational Chemistry
0202 Atomic, Molecular, Nuclear, Particle And Plasma Physics
0306 Physical Chemistry (Incl. Structural)
Publication Status
Published