Ammonium Pertechnetate in Mixtures of Trifluoromethanesulfonic Acid and Trifluoromethanesulfonic Anhydride

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 TcVI species. 99Tc nuclear magnetic resonance (NMR) has been used to study the TcVII compound and electron paramagnetic resonance (EPR), 99Tc 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 H2O. 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.

The influence of the alkoxy substituent length on the crystal structures of Tc(v) complexes with pyrazine

“…Elemental analysis (calc/find, %): Synthesis of Tc(V)OCl 2 (Pyrz) 2 OAlk Alk = Pent (5), Hex (6), Hept (7), Oct (8), Non (9), Dec (10) The synthesis of 5-10 was carried out similarly to compounds 1-4. After adding the appropriate alcohol to the technetium hydrochloric acid solution, the resulting heterogeneous mixture was stirred until the aqueous phase became discolored.…”

“…[1][2][3] For technetium with hydrogen, compounds with a formally negative oxidation statehydrideshave been registered. 4,5 The chemistry of technetium is most extensive for the Tc(V) and Tc(III) complexes; they play an important role in various fields of chemistry: preparation [6][7][8][9] and radiopharmaceuticals, 10,11 as well as in technological processes for processing technetium. 12 Attention to Tc(V) compounds is associated with the use of coordination compounds of the 99m Tc atomic isomer in radiopharmaceuticals.…”

Pertechnetates – A Structural Study Across the Periodic Table

“…Attempting to isolate pertechnetates from aqueous solutions of pertechnetic acid leads -at elevated concentrationsÀ to decomposition via formation of technetium polyoxometallates, the structures of which were only recently revealed. [28,29] This lack of knowledge prompted us to undertake a systematic study of pertechnetate salts from various elements of the periodic table. Most importantly, we present herein the usage of dilute aqueous pertechnetic acid as a precursor for the synthesis of pertechnetate salts of the alkaline earth (AE) metals, 3d transition metals I, and the lanthanoid (Ln) metals.…”

“…Attempting to isolate pertechnetates from aqueous solutions of pertechnetic acid leads – at elevated concentrations−to decomposition via formation of technetium polyoxometallates, the structures of which were only recently revealed [28,29] . This lack of knowledge prompted us to undertake a systematic study of pertechnetate salts from various elements of the periodic table.…”

Choline chloride–formic acid mixture as a medium for the reduction of pertechnetates – electrochemical and spectroscopic studies

“…19 These species were also observed by other authors. 20,21 In a less acidic environment, the dominant reduced forms of Tc are Tc(III/IV) structures or hydrated Tc(IV) oxide, while Tc(V) quickly disproportionates. 17 Ionic species containing reduced Tc may form various structures.…”