DOSY NMR and Normal Pulse Voltammetry for the Expeditious Determination of Number of Electrons Exchanged in Redox Events

Electroanalytical methods have become central tools for the development of molecular redox chemistry in the context of energy sciences and synthetic methods. Cyclic voltammetry (CV) is a routine diagnostic method for the measurement of the equilibrium potential of a redox couple. When electrochemical processes are reversible, CV may be used to determine the number of electrons involved in the redox transition. However, on the timescale of the measurement, redox couples can appear distorted due to short lifetimes of ion radicals or coupled chemical processes. In these cases, the number of electrons involved in a redox process is unclear when following the most commonly available methods. With the advent of a renaissance in electrochemistry-based synthetic methods, we report a method based on combination of techniques: Normal Pulse Voltammetry (NPV) and a routine NMR experiment: Diffusion Ordered Spectroscopy (DOSY) to enable the determination of the number of electrons, n for a redox transition of such a couple. These two measurements provide an expeditious way to determine n using commonly available equipment.