Measurements and Utilization of Consistent Gibbs Energies of Transfer of Single Ions: Towards a Unified Redox Potential Scale for All Solvents |
| |
Authors: | Dr Valentin Radtke Niklas Gebel Denis Priester Andreas Ermantraut Monika Bäuerle Dr Daniel Himmel Regina Stroh Prof Thorsten Koslowski Prof Ivo Leito Prof Ingo Krossing |
| |
Institution: | 1. Institut für Anorganische und Analytische Chemie, Freiburger Materialforschungszentrum (FMF) and, Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany;2. Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 23a, 79104 Freiburg, Germany;3. Institute of Chemistry, University of Tartu, Ravila 14a Str, 50411 Tartu, Estonia |
| |
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 - and the values that account for the electronating potential of any redox system similar to the value of a medium that accounts for its protonating potential. This 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 scale. |
| |
Keywords: | electrochemistry ionic liquids salt bridges single ion Gibbs transfer energy thermodynamics |
|
|