Surface Enrichment in Equimolar Mixtures of Non-Functionalized and Functionalized Imidazolium-Based Ionic Liquids

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Heller B, Kolbeck C, Niedermaier I, Dommer S, Schatz J, Hunt P, Maier F, Steinrück HP
Zeitschrift: ChemPhysChem
Jahr der Veröffentlichung: 2018
Band: 19
Seitenbereich: 1733-1745
ISSN: 1439-7641


Abstract

For equimolar mixtures of ionic liquids with imidazolium-based
cations of very different electronic structure, we observe very
pronounced surface enrichment effects by angle-resolved X-ray
photoelectron spectroscopy (XPS). For a mixture with the same
anion, that is, 1-methyl-3-octylimidazolium hexafluorophos
phate+1,3-di(methoxy)imidazolium hexafluorophosphate
([C8C1Im][PF6]+[(MeO)2Im][PF6]), we find a strong enrichment of
the octyl chain-containing [C8C1Im]+ cation and a correspond
ing depletion of the [(MeO)2Im]+ cation in the topmost layer.
For a mixture with different cations and anions, that is, [C8C1Im]
[Tf2N]+[(MeO)2Im][PF6], we find both surface enrichment of the
[C8C1Im]+ cation and the [Tf2N]@ (bis[(trifluoromethyl)sulfonyl]
imide) anion, while [(MeO)2Im]+ and [PF6]@ are depleted from
the surface. We propose that the observed behavior in these
mixtures is due to a lowering of the surface tension by the
enriched components. Interestingly, we observe pronounced
differences in the chemical shifts of the imidazolium ring signals
of the [(MeO)2Im]+ cations as compared to the non-functional
ized cations. Calculations of the electronic structure and the
intramolecular partial charge distribution of the cations contrib
ute to interpreting these shifts for the two different cations.






FAU-Autoren / FAU-Herausgeber

Dommer, Sabine
Professur für Organische Chemie
Heller, Bettina
Lehrstuhl für Physikalische Chemie II
Kolbeck, Claudia Dr.
Lehrstuhl für Physikalische Chemie II
Maier, Florian Dr.
Lehrstuhl für Physikalische Chemie II
Niedermaier, Inga
Lehrstuhl für Physikalische Chemie II
Schatz, Jürgen Prof. Dr.
Professur für Organische Chemie
Steinrück, Hans-Peter Prof. Dr.
Lehrstuhl für Physikalische Chemie II


Zitierweisen

APA:
Heller, B., Kolbeck, C., Niedermaier, I., Dommer, S., Schatz, J., Hunt, P.,... Steinrück, H.-P. (2018). Surface Enrichment in Equimolar Mixtures of Non-Functionalized and Functionalized Imidazolium-Based Ionic Liquids. ChemPhysChem, 19, 1733-1745. https://dx.doi.org/10.1002/cphc.201800216

MLA:
Heller, Bettina, et al. "Surface Enrichment in Equimolar Mixtures of Non-Functionalized and Functionalized Imidazolium-Based Ionic Liquids." ChemPhysChem 19 (2018): 1733-1745.

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Zuletzt aktualisiert 2019-04-01 um 17:10