Reactions of solvated electrons with imidazolium cations in ionic liquids

Abstract

We examined formation of solvated electrons in several ionic liquids composed of ammonium, pyrrolidinium and piperidinium cations by observing absorption spectra in the visible and near-infrared regions using pulse radiolysi. We also examined reactions of the solvated electrons with imidazolium cations in the ionic liquids. The reaction rate constants were an order of magnitude faster than the diffusion-limited rate calculated from the viscosity. The electrons before full solvation (dry electrons) reacted efficiently with the imidazolium cations. These observations suggest that the electrons in the ionic liquids can move easily before solvation. The scavenging of the dry electron by the imidazolium cation was also examined using C2-alkylated-imidazolium cations. It is found that the alkylation of imidazolium suppresses the reactivity with the dry electron.