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Measurements and Utilization of Consistent Gibbs Energies of Transfer of Single Ions: Towards a Unified Redox Potential Scale for All Solvents
Author(s) -
Radtke Valentin,
Gebel Niklas,
Priester Denis,
Ermantraut Andreas,
Bäuerle Monika,
Himmel Daniel,
Stroh Regina,
Koslowski Thorsten,
Leito Ivo,
Krossing Ingo
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202200509
Subject(s) - redox , gibbs free energy , propylene carbonate , chemistry , solvation , ion , aqueous solution , acetonitrile , thermodynamics , solvent , standard electrode potential , inorganic chemistry , chemical physics , electrochemistry , organic chemistry , electrode , physics
Utilizing the “ideal” ionic liquid salt bridge to measure Gibbs energies of transfer of silver ions between the solvents water, acetonitrile, propylene carbonate and dimethylformamide results in a consistent data set with a precision of 0.6 kJ mol −1 over 87 measurements in 10 half‐cells. This forms the basis for a coherent experimental thermodynamic framework of ion solvation chemistry. In addition, we define the solvent independent pe absH 2 O ‐ and the E absH 2 Ovalues that account for the electronating potential of any redox system similar to the pH absH 2 Ovalue of a medium that accounts for its protonating potential. This E absH 2 Oscale is thermodynamically well‐defined enabling a straightforward comparison of the redox potentials (reducities) of all media with respect to the aqueous redox potential scale, hence unifying all conventional solvents′ redox potential scales. Thus, using the Gibbs energy of transfer of the silver ion published herein, one can convert and unify all hitherto published redox potentials measured, for example, against ferrocene, to the E absH 2 Oscale.