On the Aqueous Chemistry of the UIV–DOTA Complex

Gev Dovrat, Marie Claire Illy, Claude Berthon, Ana Lerner, Moshe H. Mintz, Eric Maimon, Radion Vainer, Yeshayahu Ben-Eliyahu, Yulia Moiseev, Philippe Moisy, Armand Bettelheim, Israel Zilbermann

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) aqueous complex of UIV with H2O, OH, and F as axial ligands was studied by using UV/Vis spectrophotometry, ESI-MS, NMR spectroscopy, X-ray crystallography, and electrochemistry. The UIV–DOTA complex with either water or fluoride as axial ligands was found to be inert to oxidation by molecular oxygen, whereas the complex with hydroxide as an axial ligand slowly hydrolyzed and was oxidized by dioxygen to a diuranate precipitate. The combined data set acquired shows that, although axial substitution of fluoride and hydroxide ligands instead of water does not seem to significantly change the aqueous DOTA complex structure, it has an important effect on the electronic configuration of the complex. The UIV/UIII redox couple was found to be quasi-reversible for the complex with both axially bonded H2O and hydroxide, but irreversible for the complex with axially bonded fluoride. Intriguingly, binding of the axial fluoride renders the irreversible one-electron UV/UIV oxidation of the [UIV(DOTA)(H2O)] complex quasi-reversible, which suggests the formation of the short-lived pentavalent form of the complex, an aqueous non-uranyl chelated UV cation.

Original languageEnglish
Pages (from-to)3390-3403
Number of pages14
JournalChemistry - A European Journal
Volume26
Issue number15
DOIs
StatePublished - 12 Mar 2020

Keywords

  • electrochemistry
  • ligand effects
  • redox chemistry
  • structure elucidation
  • uranium

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