Organic electrochemistry in ionic liquids

The reductive electrochemistry of dimethylmaleate and benzaldehyde in room temperature ionic liquids is described. The reduction of the activated olefin involves a one-electron process in a similar fashion to that observed in organic solvent based electrolytes. The reduction of benzaldehyde also exhibits a one-electron reduction process; however, two additional well defined and separated reduction processes are observed at more negative potentials. These have been attributed to the alpha-hydroxybenzyl radical and the benzaldehyde radical anion. It appears that the remarkable stability of these radical pairs may be due to interaction with the ionic liquid. Also, because of the stability of ionic liquids to electrolysis, and because they tend to stabilise free radical species, they can provide a straightforward means to study radical chemistry.