4.6 Article

Quenching Mechanism of Uranyl(VI) by Chloride and Bromide in Aqueous and Non-Aqueous Solutions

Journal

JOURNAL OF PHYSICAL CHEMISTRY A
Volume 125, Issue 20, Pages 4380-4389

Publisher

AMER CHEMICAL SOC
DOI: 10.1021/acs.jpca.1c02487

Keywords

-

Funding

  1. Federal Ministry for Economic Affairs and Energy [02E11415F, 02E11860]

Ask authors/readers for more resources

The study demonstrates that the use of specific organic solvents can suppress the quenching of uranyl(VI) luminescence, reigniting its fluorescence. Quenching occurs through the outer-sphere complex of U(VI) and halide in water, while the ligand-to-metal charge transfer is reduced in acetonitrile.
A major hindrance in utilizing uranyl(VI) luminescence as a standard analytical tool, for example, in environmental monitoring or nuclear industries, is quenching by other ions such as halide ions, which are present in many relevant matrices of uranyl(VI) speciation. Here, we demonstrate through a combination of time-resolved laser-induced fluorescence spectroscopy, transient absorption spectroscopy, and quantum chemistry that coordinating solvent molecules play a crucial role in U(VI) halide luminescence quenching. We show that our previously suggested quenching mechanism based on an internal redox reaction of the 1:2-uranyl-halide-complex holds also true for bromide-induced quenching of uranyl(VI). By adopting specific organic solvents, we were able to suppress the separation of the oxidized halide ligand X-2(center dot-) and the formed uranyl(V) into fully solvated ions, thereby reigniting U(VI) luminescence. Time-dependent density functional theory calculations show that quenching occurs through the outer-sphere complex of U(VI) and halide in water, while the ligand-to-metal charge transfer is strongly reduced in acetonitrile.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available