An investigation of trioctylmethylammonium ionic liquids by X-ray photoelectron spectroscopy: The cation-anion interaction

In this study, two trioctylmethylammonium ionic liquids were investigated using X-ray photoelectron spectroscopy, together with two binary ionic liquid mixtures. The interaction between the cation and the anion is demonstrated in detail. The effect of both the anion basicity and the cation acidity on the charge transferred from the anion to the cation is explored. By using ionic liquid mixtures with binary cations, the electronic environment of the anion can be effectively tuned. XPS data can be used to reflect such subtle change.