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Influence of the substituent on the major decomposition channels of the NO 2 group in para ‐substituted nitrobenzenes: a tandem mass spectrometric study
Author(s) -
Brill T. B.,
James K. J.,
Chawla R.,
Nicol G.,
Shukla A.,
Futrell J. H.
Publication year - 1999
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199911)12:11<819::aid-poc192>3.0.co;2-r
Subject(s) - chemistry , substituent , fragmentation (computing) , nitrobenzene , photochemistry , tandem mass spectrometry , polar effect , nitro , electron ionization , collision induced dissociation , dissociation (chemistry) , isomerization , mass spectrometry , ion , medicinal chemistry , ionization , organic chemistry , alkyl , chromatography , computer science , operating system , catalysis
The relative extents of loss of NO 2 and NO were determined by 70 eV electron ionization and tandem mass spectrometry using B/E linked scans to investigate metastable (unimolecular) and collision‐induced dissociation processes for molecular ions formed by electron ionization of para ‐substituted nitrobenzene compounds. The substituents used (NO 2 , CHO, H, OCH 3 ) represent a wide range of electron donor–acceptor properties. Loss of NO 2 was favored by electron‐withdrawing groups, while an electron‐donor group favored loss of NO. Ion fragmentation mechanisms are consistent with the hypothesis that NO 2 to ONO (nitro to nitrite) isomerization precedes the loss of NO. Ring fragmentation (loss of CO) was observed only after all of the electron‐withdrawing groups had dissociated. while the electron‐donor group OCH 3 remained attached to the ring in the analogous CO elimination. These results are placed in the context of the thermolysis behavior of nitroaromatic explosives. Copyright © 1999 John Wiley & Sons, Ltd.