X-ray photoelectron spectroscopy of sulfonium ionic liquids: Probing the impact of alkyl substituent on the electronic environment of the anion

Abstract

In this study, five sulfonium ionic liquids are analysed by X-ray photoelectron spectroscopy. The surface purity and C 1s fitting model are discussed in details. The influence of alkyl chain length on the aliphatic carbon binding energy is illustrated by comparing ethyl- and butyl-based cations. The impact of the cation on the electronic environment of the anion-based components is demonstrated. It is found that the cation-anion interactions can be significantly affected by the structure of the cation.