Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 21, 2020
Previous Article Next Article

Temperature-dependent luminescence spectroscopic investigations of uranyl(vi) complexation with the halides F and Cl

Author affiliations

Abstract

In the present study we have investigated the complexation of uranyl(VI) with chloride and fluoride using luminescence spectroscopy (TRLFS, time-resolved laser-induced fluorescence spectroscopy). At 25 °C (298.15 K), in the presence of 0–0.175 M fluoride, the first single-component emission spectra for all four uranyl(VI)-fluoride complexes, i.e. UO2F+, UO2F2, UO2F3, and UO2F42− could be extracted. Based on the aqueous speciation derived from the TRLFS data, log K* values at I = 1 M were calculated for all these complexes and extrapolated to infinite dilution using the SIT approach. In the case of chloride, however, quenching of the uranyl(VI)-luminescence hampered the experiments. Thus, uranyl(VI)-complexation was studied with TRLFS at liquid nitrogen temperatures. Samples were prepared at 25 °C (298.15 K) with chloride concentrations ranging from 0 to 1.0 M followed by instantaneous freezing and subsequent luminescence spectroscopic measurements at −120 °C (153.15 K). This allowed for the determination of the first luminescence spectra for the UO2Cl+ complex with the TRLFS method. The chloride quench reaction was further studied in the temperature range 1–45 °C (274.15–318.15 K) using Stern–Volmer analysis. By applying the Arrhenius and the Eyring equations we obtained the first thermodynamic parameters for the dynamic quench process, i.e. the activation energy (Ea = 55.0 ± 12.9 kJ mol−1), enthalpy (ΔH = 52.5 ± 13.0 kJ mol−1), and entropy (ΔS = 103.9 ± 42.8 J mol−1 K−1).

Graphical abstract: Temperature-dependent luminescence spectroscopic investigations of uranyl(vi) complexation with the halides F− and Cl−

Back to tab navigation

Supplementary files

Article information


Submitted
20 Feb 2020
Accepted
01 May 2020
First published
04 May 2020

Dalton Trans., 2020,49, 7109-7122
Article type
Paper

Temperature-dependent luminescence spectroscopic investigations of uranyl(VI) complexation with the halides F and Cl

M. Demnitz, S. Hilpmann, H. Lösch, F. Bok, R. Steudtner, M. Patzschke, T. Stumpf and N. Huittinen, Dalton Trans., 2020, 49, 7109
DOI: 10.1039/D0DT00646G

Social activity

Search articles by author

Spotlight

Advertisements