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Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids

Kallidanthiyil Chellappan Lethesh, Kristof Van Hecke UGent, Luc Van Meervelt, Peter Nockemann, Barbara Kirchner, Stefan Zahn, Tatjana N Parac-Vogt, Wim Dehaen and Koen Binnemans (2011) JOURNAL OF PHYSICAL CHEMISTRY B. 115(26). p.8424-8438
abstract
Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids fiinctionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The (15)N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the (15)N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
SENSITIZED SOLAR-CELLS, SOLUBILIZING METAL-OXIDES, N-15 NMR-SPECTROSCOPY, VIBRATIONAL-SPECTRA, STRUCTURAL-ANALYSIS, COUPLING REACTIONS, N-ETHYLPYRIDINIUM, PHOSPHINE-LIGANDS, BASIS-SETS, SALTS
journal title
JOURNAL OF PHYSICAL CHEMISTRY B
J. Phys. Chem. B
volume
115
issue
26
pages
8424 - 8438
Web of Science type
Article
Web of Science id
000292281200007
JCR category
CHEMISTRY, PHYSICAL
JCR impact factor
3.696 (2011)
JCR rank
32/129 (2011)
JCR quartile
1 (2011)
ISSN
1520-6106
DOI
10.1021/jp2027675
language
English
UGent publication?
no
classification
A1
id
2045531
handle
http://hdl.handle.net/1854/LU-2045531
date created
2012-02-27 11:02:18
date last changed
2018-01-29 12:12:31
@article{2045531,
  abstract     = {Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids fiinctionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The (15)N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the (15)N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom.},
  author       = {Lethesh, Kallidanthiyil Chellappan and Van Hecke, Kristof and Van Meervelt, Luc and Nockemann, Peter and Kirchner, Barbara and Zahn, Stefan and Parac-Vogt, Tatjana N and Dehaen, Wim and Binnemans, Koen},
  issn         = {1520-6106},
  journal      = {JOURNAL OF PHYSICAL CHEMISTRY B},
  keyword      = {SENSITIZED SOLAR-CELLS,SOLUBILIZING METAL-OXIDES,N-15 NMR-SPECTROSCOPY,VIBRATIONAL-SPECTRA,STRUCTURAL-ANALYSIS,COUPLING REACTIONS,N-ETHYLPYRIDINIUM,PHOSPHINE-LIGANDS,BASIS-SETS,SALTS},
  language     = {eng},
  number       = {26},
  pages        = {8424--8438},
  title        = {Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids},
  url          = {http://dx.doi.org/10.1021/jp2027675},
  volume       = {115},
  year         = {2011},
}

Chicago
Lethesh, Kallidanthiyil Chellappan, Kristof Van Hecke, Luc Van Meervelt, Peter Nockemann, Barbara Kirchner, Stefan Zahn, Tatjana N Parac-Vogt, Wim Dehaen, and Koen Binnemans. 2011. “Nitrile-functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids.” Journal of Physical Chemistry B 115 (26): 8424–8438.
APA
Lethesh, K. C., Van Hecke, K., Van Meervelt, L., Nockemann, P., Kirchner, B., Zahn, S., Parac-Vogt, T. N., et al. (2011). Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids. JOURNAL OF PHYSICAL CHEMISTRY B, 115(26), 8424–8438.
Vancouver
1.
Lethesh KC, Van Hecke K, Van Meervelt L, Nockemann P, Kirchner B, Zahn S, et al. Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids. JOURNAL OF PHYSICAL CHEMISTRY B. 2011;115(26):8424–38.
MLA
Lethesh, Kallidanthiyil Chellappan, Kristof Van Hecke, Luc Van Meervelt, et al. “Nitrile-functionalized Pyridinium, Pyrrolidinium, and Piperidinium Ionic Liquids.” JOURNAL OF PHYSICAL CHEMISTRY B 115.26 (2011): 8424–8438. Print.