Coexistence of Tellurium Cations and Anions in Phosphonium‐Based Ionic Liquids

Elemental tellurium readily dissolves in ionic liquids (ILs) based on tetraalkylphosphonium cations even at temperatures below 100 °C. In the case of ILs with acetate, decanoate, or dicyanamide anions, dark red to purple colored solutions form. A study combining NMR, UV‐Vis and Raman spectroscopy re...

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Bibliographic Details
Published in:Chemistry : a European journal 2022-02, Vol.28 (7), p.e202103770-n/a
Main Authors: Grasser, Matthias A., Pietsch, Tobias, Blasius, Jan, Hollóczki, Oldamur, Brunner, Eike, Doert, Thomas, Ruck, Michael
Format: Article
Language:English
Subjects:
125Te NMR spectroscopy
Acetic acid
Anions
Cations
Chemistry
Coexistence
Disproportionation
Electrostatic properties
Ionic liquids
Ions
NMR
Nuclear magnetic resonance
Raman spectroscopy
tellurides
Tellurium
tellurium cations
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Summary:Elemental tellurium readily dissolves in ionic liquids (ILs) based on tetraalkylphosphonium cations even at temperatures below 100 °C. In the case of ILs with acetate, decanoate, or dicyanamide anions, dark red to purple colored solutions form. A study combining NMR, UV‐Vis and Raman spectroscopy revealed the formation of tellurium anions (Ten)2− with chain lengths up to at least n=5, which are in dynamic equilibrium with each other. Since external influences could be excluded and no evidence of an ionic liquid reaction was found, disproportionation of the tellurium is the only possible dissolution mechanism. Although the spectroscopic detection of tellurium cations in these solutions is difficult, the coexistence of tellurium cations, such as (Te4)2+ and (Te6)4+, and tellurium anions could be proven by cyclic voltammetry and electrodeposition experiments. DFT calculations indicate that electrostatic interactions with the ions of the ILs are sufficient to stabilize both types of tellurium ions in solution. Grey tellurium dissolves under disproportionation in the ionic liquids [P66614][OAc] and [P4444][OAc] at ambient temperatures. The stable red‐purple solutions contain tellurium cations, such as (Te4)2+ and (Te6)4+, and anions (Ten)2− with chain lengths up to at least n=5, as evidenced by spectroscopic and electrochemical techniques. DFT calculations indicate that electrostatic interactions with the components of the ILs stabilize tellurium cations and anions in solution.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.202103770