Abstract
In this study, nine piperidinium-based ionic liquids are analysed by X-ray photoelectron spectroscopy. The effect of alkyl substituent length and the nature of the anion on the electronic environment of the cation are investigated. The electronic environment of the hetero carbon and the cationic nitrogen is compared between two structurally similar cations, 1-octyl-1-methylpiperidinium ([C8C1Pip]+)versus1-octylpyridinium ([C8Py]+). Due to the charge delocalisation, the hetero carbon component within [C8Py]+is more positively charged, which exhibits much higher binding energy; whilst the cationic nitrogen component is in the similar electronic environment. The impact of the charge delocalisation on the electronic environment of the anion is also compared between [C8C1Pip]+and [C8Py]+. It is found that for the more basic anion, the cation can significantly affect the electronic environment of the anion; for the less basic anion, such an effect concentrates on the component bearing more negative point charges.
| Original language | English |
|---|---|
| Pages (from-to) | 11976-11983 |
| Number of pages | 8 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 22 |
| Issue number | 21 |
| DOIs | |
| State | Published - Jun 7 2020 |
Funding
SM thanks Liaoning Provincial Foundation of Science and Technology (20180550482) for financial support. SM is also grateful to China Scholarship Council for the grant of a scholarship under State Scholarship Fund (201808210439) as a Visiting Scholar in Oak Ridge National Laboratory (ORNL). HML and SD are partly supported by U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. Drs Jun Qu and Harry Meyer III from ORNL are acknowledged for XPS training and helpful discussions.