Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy

Witt M, Grützmacher H-F (1997)
INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 165-166: 49-62.

Journal Article | Published | English

No fulltext has been uploaded

Author
Abstract
The gas phase basicity of butyramide (2a), caproamide (3a), isobutyramide (5a), pivalamide (6a), cyclopentanecarboxamide (7a), cyclohexanecarboxamide (8a), their N-methyl derivatives 2b-8b and their N,N-dimethyl derivatives 2c-8c have been determined by the 'deprotonation' method using FT-ICR spectrometry (2a-8a only) and by the 'kinetic' method observing the metastable decomposition of proton-bound heterodimers by tandem mass spectrometry. Both methods give identical results for the primary carboxamides studied within the limit of error of +/- 6 kJ/mol. The GB(2a-8a) and PA(2a-8a) correlate linearly with the GB and PA of other aliphatic carbonyl compounds (aldehydes, ketones, methyl carboxylates) as expected for a protonation of the carboxamides at the carbonyl-O atom. The GB of the N-methyl- and N,N-dimethylcarboxamides exceed the GB of the primary carboxamides by 22 +/- 3 kJ/mol and 46 +/- 4 kJ/mol, respectively. The bond dissociation energy BDE of the proton-bound homodimer of formamide, acetamide, propionamide and pivalamide and of their N,N-dimethyl derivatives have been derived from the appearance energy AE of the protonated carboxamide from the proton-bound homodimers using collision energy resolved mass spectrometry GERMS (collision energy resolved mass spectrometry) by FT-ICR spectrometry. The BDE of all proton-bound dimers of the primary carboxamides measured are virtually constant at 1.19 +/- 0.08 eV in spite of a considerable variation of the GB by 0.68 eV. The BDE of the proton-bound homodimers of the N,N-dimethylcarboxamides are consistently smaller than those of the primary carboxamides in spite of the increased GB of tertiary carboxamides and decreases from the proton-bound homodimer of N,N-dimethylformamide to N,N-dimethylpivalamide. As a consequence of this effect formamide of the lowest GB exhibits the highest BDE in its proton-bound homodimer while N,N-dimethylpivalamide with the highest GB forms the weakest ionic hydrogen bond. (C) 1997 Elsevier Science B.V.
Publishing Year
ISSN
PUB-ID

Cite this

Witt M, Grützmacher H-F. Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY. 1997;165-166:49-62.
Witt, M., & Grützmacher, H. - F. (1997). Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, 165-166, 49-62.
Witt, M., and Grützmacher, H. - F. (1997). Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 165-166, 49-62.
Witt, M., & Grützmacher, H.-F., 1997. Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, 165-166, p 49-62.
M. Witt and H.-F. Grützmacher, “Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy”, INTERNATIONAL JOURNAL OF MASS SPECTROMETRY, vol. 165-166, 1997, pp. 49-62.
Witt, M., Grützmacher, H.-F.: Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY. 165-166, 49-62 (1997).
Witt, Matthias, and Grützmacher, Hans-Friedrich. “Proton-bound dimers of aliphatic carboxamides: gas-phase basicity and dissociation energy”. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 165-166 (1997): 49-62.
This data publication is cited in the following publications:
This publication cites the following data publications:

Export

0 Marked Publications

Open Data PUB

Web of Science

View record in Web of Science®

Search this title in

Google Scholar