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{Gehrke:2019:10.1002/ejoc.201801050,
author = {Gehrke, S and Reckien, W and Palazzo, I and Welton, T and Hollóczki, O},
doi = {10.1002/ejoc.201801050},
journal = {European Journal of Organic Chemistry},
pages = {504--511},
title = {On the Carbene-Like Reactions of Imidazolium Acetate Ionic Liquids: Can Theory and Experiments Agree?},
url = {http://dx.doi.org/10.1002/ejoc.201801050},
volume = {2019},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - © 2019 WILEY-VCH Verlag GmbH  &  Co. KGaA, Weinheim The N-heterocyclic carbene organocatalytic reactivity of the 1-ethyl-3-methylimidazolium acetate ionic liquid was investigated on the model reaction between this solvent and anisaldehyde. The formation of carbenes by a proton transfer from the cation to the anion was compared to a direct reaction mechanism, in which the proton transfer and the C–C bond formation between catalyst and substrate occurs in a single elementary step. Interestingly, the two reaction mechanisms show a much smaller difference in activation energies than those observed for analogous catalytic systems with neutral bases, showing that the mechanism might switch from one to the other at different temperatures or with different substrates. In this particular case, however, the direct reaction mechanism, avoiding free carbenes in the solution, is apparently more feasible. Based on the detailed analysis of this reaction path, the earlier contradictions between theory and experiments can be resolved, resulting in a consistent mechanistic picture for the related processes. Additionally, we show on the example of a platinum surface that introducing metal probes into the liquid may induce carbene-like reactions, as the formation of a strong coordinative bond between the carbene and a platinum atom at the surface is highly exothermic, shifting the acid-base equilibrium considerably.
AU  - Gehrke,S
AU  - Reckien,W
AU  - Palazzo,I
AU  - Welton,T
AU  - Hollóczki,O
DO  - 10.1002/ejoc.201801050
EP  - 511
PY  - 2019///
SN  - 1434-193X
SP  - 504
TI  - On the Carbene-Like Reactions of Imidazolium Acetate Ionic Liquids: Can Theory and Experiments Agree?
T2  - European Journal of Organic Chemistry
UR  - http://dx.doi.org/10.1002/ejoc.201801050
VL  - 2019
ER  -
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