Solvent effects on the prediction of redox potentials: Application to nitroxides

This paper investigates the impact of solute-solvent interactions on the redox potentials of nitroxides, with a focus on ionic interactions caused by the presence of electrolytes found in different environment such as batteries. The analysis of various nitroxide families shows that ion-substituent interactions, especially in aromatic systems, significantly influence complex stability. Indeed, the counterion typically prefers to position near the substituent. However, in acetonitrile, the hydroxylamine anion and its cation show strong interactions when the cation is near the nitroxyl moiety. The study also confirm that an electrostatic interaction model can predict the effects of substituents, aromaticity, and ring size on redox potentials of nitroxides. Concerning the impact of the environment, solute-ion interactions and ion-pairs formation play a crucial role in modulating the redox potential.