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A study of some cations formed in the ammonia chemical ionization of ketones using mass analysed ion kinetic energy spectrometry
Author(s) -
Maquestiau André,
Flammang Robert,
Nielsen Lawrence
Publication year - 1980
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210150712
Subject(s) - protonation , chemistry , ketone , ammonia , adduct , mass spectrometry , ion , chemical ionization , imine , hydrogen , ammonium , ionization , inorganic chemistry , medicinal chemistry , photochemistry , organic chemistry , chromatography , catalysis
The structures of the major adduct ions formed in ammonia chemical ionization of thirteen aliphatic and aromatic ketones have been studied by mass analysed ion kinetic energy spectrometry. The [M+NH 3 +H] + ion is shown to have a protonated carbinolamine structure, [M+2NH 3 +H] + to be a protonated carbinolamine with hydrogen‐bonded ammonia and [2M+NH 3 +H] + to be, at least in part, a protonated carbinolamine with hydrogen‐bonded ketone. These structures may imply a nucleophilic addition of ammonia at the carbonyl of the ketone‐ammonium ion complex. An unusual hydroxy migration is seen in the internal rearrangement of the [2M+NH 3 +H] + ion leading to the formation of a protonated imine.