Electrochemical behaviour of tetra-n-butylammonium nonaflate as an ionic liquid and as a supporting electrolyte in aprotic solvents: A comparative study

Tetra-n-butylammonium nonaflate was synthesized, characterized and employed as a neat ionic liquid and as supporting electrolyte in acetonitrile, N,N′-dimethylformamide, propylene carbonate and sulfolane media. The electrochemical oxidation of ferrocene and hydroquinone as well as the electrochemical reduction of anthracene were investigated in all the media. Good correlation is established between the charge transfer rate, diffusion coefficient of all the three redox species and the viscosity of the five electrolyte media employed. The viscosity dependent solvation dynamics of the redox molecules thus appear to influence the charge transfer and mass transport behaviour in quite similar fashion over a wide viscosity range. The chemical stability and stability of electrogenerated free radicals however depend on the nature of the solvent rather than the viscosity.