title: X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues.
abstract: We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids.
authors.affiliation: School of Material Science and Engineering, Shenyang Ligong University, Shenyang 110168 (P. R. China). menshuang@hotmail.com.|School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK). menshuang@hotmail.com.
authors.forename: Shuang
authors.initials: S
authors.lastname: Men
authors.affiliation: School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK).
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Mitchell
authors.affiliation: Department of Chemistry, Imperial College London, London SW7 2AZ (UK).
authors.forename: Kevin R J
authors.initials: KR
authors.lastname: Lovelock
authors.affiliation: School of Chemistry, The University of Nottingham, Nottingham NG7 2RD (UK). peter.licence@nottingham.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Licence
keywords: X-ray photoelectron spectroscopy; binding energy; fitting model; ionic liquids; pyridinium