Ammonium Pertechnetate in Mixtures of Trifluoromethanesulfonic Acid and Trifluoromethanesulfonic Anhydride

Markus Zegke; Dennis Grödler; Maximilian Roca Jungfer; Alexander Haseloer; Meike Kreuter; Jörg M Neudörfl; Thomas Sittel; Christopher M James; Jörg Rothe; Marcus Altmaier; Axel Klein; Martin Breugst; Ulrich Abram; Erik Strub; Mathias S Wickleder

doi:10.1002/anie.202113777

Ammonium Pertechnetate in Mixtures of Trifluoromethanesulfonic Acid and Trifluoromethanesulfonic Anhydride

Angew Chem Int Ed Engl. 2022 Jan 17;61(3):e202113777. doi: 10.1002/anie.202113777. Epub 2021 Dec 3.

Authors

Affiliations

¹ University of Cologne, Department of Chemistry, Institute for Inorganic Chemistry, Greinstrasse 4-6, 50939, Cologne, Germany.
² Freie Universität Berlin, Institute for Chemistry and Biochemistry, Inorganic Chemistry, Fabeckstrasse 34-36, 14195, Berlin, Germany.
³ University of Cologne, Department of Chemistry, Division of Nuclear Chemistry, Zülpicher Strasse 45, 50674, Cologne, Germany.
⁴ University of Cologne, Department of Chemistry, Institute for Organic Chemistry, Greinstrasse 4-6, 50939, Cologne, Germany.
⁵ Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.

Abstract

Ammonium pertechnetate reacts in mixtures of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid under final formation of ammonium pentakis(trifluoromethanesulfonato)oxidotechnetate(V), (NH₄ )₂ [TcO(OTf)₅ ]. The reaction proceeds only at exact concentrations and under the exclusion of air and moisture via pertechnetyl trifluoromethanesulfonate, [TcO₃ (OTf)], and intermediate Tc^VI species. ⁹⁹ Tc nuclear magnetic resonance (NMR) has been used to study the Tc^VII compound and electron paramagnetic resonance (EPR), ⁹⁹ Tc NMR and X-ray absorption near-edge structure (XANES) experiments indicate the presence of the reduced technetium species. In moist air, (NH₄ )₂ [TcO(OTf)₅ ] slowly hydrolyses under formation of the tetrameric oxidotechnetate(V) (NH₄ )₄ [{TcO(TcO₄ )₄ }₄ ] ⋅10 H₂ O. Single-crystal X-ray crystallography was used to determine the solid-state structures. Additionally, UV/Vis absorption and IR spectra as well as quantum chemical calculations confirm the identity of the species.

Keywords: anhydride; pertechnetate; reduction; super acid; trifluoromethanesulfonic acid.

Abstract

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