Measurements and Utilization of Consistent Gibbs Energies of Transfer of Single Ions: Towards a Unified Redox Potential Scale for All Solvents. Issue 40 (31st May 2022)

• Record Type: Journal Article
• Authors: Radtke, Valentin; Gebel, Niklas; Priester, Denis; Ermantraut, Andreas; Bäuerle, Monika; Himmel, Daniel; Stroh, Regina; Koslowski, Thorsten; Leito, Ivo; Krossing, Ingo
• Is Part Of: Chemistry. Volume 28:Issue 40(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-31
• Subjects: electrochemistry -- ionic liquids -- salt bridges -- single ion Gibbs transfer energy -- thermodynamics; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202200509
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: 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 abs H 2 O ‐ and the E abs H 2 O values that account for the electronating potential of any redox system similar to the pH abs H 2 O value of a medium that accounts for its protonating potential. This E abs H 2 O scale 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 abs H 2 O scale. Abstract : Consistency : 87 measurements across 10 independent junctions between four solvents and using the "ideal" ionic liquid salt bridge ILSB have furnished accurate silver ion Gibbs transfer energies between water, acetonitrile, propylene carbonate and dimethylformamide that are consistent within 0.6 kJ mol −1 . These form the basis for a coherent experimental thermodynamic framework of ion solvation chemistry.