Imperial College London
Portrait Picture

Professor Tom Welton

Faculty of Natural Sciences, Department of Chemistry

Professor of Sustainable Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 5763t.welton Website

 
 
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Location

 

601AMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Rauber:2023:10.1016/j.jil.2023.100060,
author = {Rauber, D and Philippi, F and Morgenstern, B and Zapp, J and Kuttich, B and Kraus, T and Welton, T and Hempelmann, R and Kay, CWM},
doi = {10.1016/j.jil.2023.100060},
journal = {Journal of Ionic Liquids},
title = {Dynamics, cation conformation and rotamers in guanidinium ionic liquids with ether groups},
url = {http://dx.doi.org/10.1016/j.jil.2023.100060},
volume = {3},
year = {2023}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Ionic liquids are modern materials with a broad range of applications, including electrochemical devices, the exploitation of sustainable resources and chemical processing. Expanding the chemical space to include novel ion classes allows for the elucidation of novel structure-property relationships and fine tuning for specific applications. We prepared a set of ionic liquids based on the sparsely investigated pentamethyl guanidinium cation with a 2-ethoxy-ethyl side chain in combination with a series of frequently used anions. The resulting properties are compared to a cation with a pentyl side chain lacking ether functionalization. We measured the thermal transitions and transport properties to estimate the performance and trends of this cation class. The samples with imide-type anions form liquids at ambient temperature, and show good transport properties, comparable to imidazolium or ammonium ionic liquids. Despite the dynamics being significantly accelerated, ether functionalization of the cation favors the formation of crystalline solids. Single crystal structure analysis, ab initio calculations and variable temperature nuclear magnetic resonance measurements (VT-NMR) revealed that cation conformations for the ether- and alkyl-chain-substituted are different in both the solid and liquid states. While ether containing cations adopt compact, curled structures, those with pentyl side chains are linear. The Eyring plot revealed that the curled conformation is accompanied by a higher activation energy for rotation around the carbon-nitrogen bonds, due to the coordination of the ether chain as observed by VT-NMR.
AU  - Rauber,D
AU  - Philippi,F
AU  - Morgenstern,B
AU  - Zapp,J
AU  - Kuttich,B
AU  - Kraus,T
AU  - Welton,T
AU  - Hempelmann,R
AU  - Kay,CWM
DO  - 10.1016/j.jil.2023.100060
PY  - 2023///
TI  - Dynamics, cation conformation and rotamers in guanidinium ionic liquids with ether groups
T2  - Journal of Ionic Liquids
UR  - http://dx.doi.org/10.1016/j.jil.2023.100060
VL  - 3
ER  -
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