Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry

Thölmann D, Flottmann D, Grützmacher H-F (1991)
Chemische Berichte 124(10): 2349-2356.

Zeitschriftenaufsatz | Veröffentlicht | Englisch
 
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Thölmann, Detlef; Flottmann, Dirk; Grützmacher, Hans-FriedrichUniBi
Abstract / Bemerkung
The gas-phase reactions of the three isomeric dichloroethene radical cations 1 + -3 + with NH 3 and of the neutral species 1-3 and the isomeric 1,2-dibromoethenes 4 and 5 with CH 3-NH 2 +. and (CH 3) 2NH + , respectively, are studied by Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) mass spectrometry. A chloro substituent in 1 + -3 + is replaced by NH 3 in a fast reaction, yielding C 2H 5NCl + ions. These substitution reactions are very fast and occur nearly at the collision limit. The 1,1-dichloroethene radical cations 3 + exchange successively both Cl substituents, yielding C 2H 7N 2 + ions and eventually cluster ions N 2H 7 +. Substitution takes place also by the reaction of neutral haloethenes 1-5 with amine radical cations, although at very different rates. The efficiencies of the reactions of CH 3HN 2 + with 1-5 are quite large, but those of the reactions of (CH 3) 2NH + with 1 and 2 are < 1% and reach only 10% even in the case of the bromoethenes 4 and 5. 1,1-Dichlorethene (3) does not react at all. An addition-elimination mechanism is proposed for all these reactions, giving rise to the formation of intermediate -distonic ammonium ions. This reaction path and the stability of the intermediates are supported by MNDO calculations. However, the intermediate -distonic ions have to isomerize further by hydrogen shifts before the product ions are eventually formed. MNDO calculations support the assumption that the slow reactions of (CH 3) 2NH + with the haloethenes are due to slow rearrangements within the initially formed distonic ions, which have to precede the loss of Cl.
Stichworte
nucleophilic; Substitution; Ion-molecule reactions; MNDO; Calculations; FT-ICR mass spectrometry; Radical cations
Erscheinungsjahr
1991
Zeitschriftentitel
Chemische Berichte
Band
124
Ausgabe
10
Seite(n)
2349-2356
ISSN
0009-2940
eISSN
1099-0682
Page URI
https://pub.uni-bielefeld.de/record/1783434

Zitieren

Thölmann D, Flottmann D, Grützmacher H-F. Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry. Chemische Berichte. 1991;124(10):2349-2356.
Thölmann, D., Flottmann, D., & Grützmacher, H. - F. (1991). Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry. Chemische Berichte, 124(10), 2349-2356. doi:10.1002/cber.19911241031
Thölmann, D., Flottmann, D., and Grützmacher, H. - F. (1991). Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry. Chemische Berichte 124, 2349-2356.
Thölmann, D., Flottmann, D., & Grützmacher, H.-F., 1991. Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry. Chemische Berichte, 124(10), p 2349-2356.
D. Thölmann, D. Flottmann, and H.-F. Grützmacher, “Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry”, Chemische Berichte, vol. 124, 1991, pp. 2349-2356.
Thölmann, D., Flottmann, D., Grützmacher, H.-F.: Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry. Chemische Berichte. 124, 2349-2356 (1991).
Thölmann, Detlef, Flottmann, Dirk, and Grützmacher, Hans-Friedrich. “Gas-phase substitution of dichloro- and dibromoethene by ammonia and amines via radical cations: a kinetic study by FT-ICR spectrometry”. Chemische Berichte 124.10 (1991): 2349-2356.
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