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Collisional activation spectra of the adduct ions of 1,2,3‐triarylpropenones under ammonia chemical ionization conditions
Author(s) -
Madhusudanan K. P.,
Durani S.,
Kapil R. S.,
Fraisse D.
Publication year - 1990
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.1210250504
Subject(s) - adduct , chemistry , ion , dissociation (chemistry) , ammonia , ionization , mass spectrometry , chemical ionization , mass spectrum , fragmentation (computing) , ketone , decomposition , hydrogen , photochemistry , organic chemistry , chromatography , computer science , operating system
Under ammonia chemical ionization (CI) conditions triarylpropenones undergo hydrogen radical‐induced olefinic bond reduction on metal surfaces, resulting in [M + 2H + NH 4 ] + ions corresponding to the ammonium adduct of the saturated ketone. The decomposition of the adduct ions, [MNH 4 ] + and [M + 2H + NH 4 ] + , was studied by collision‐induced dissociation mass‐analysed ion kinetic energy (CID‐MIKE) spectroscopy in a reverse geometry instrument. From the CID‐MIKE spectra of the [MNH 4 ] + , [M + 2H + NH 4 ] + , [MND 4 ] + and [M + 2D + ND 4 ] + ions it is clear that the fragmentation of the adduct ions involves loss of NH 3 followed by various cyclization reactions resulting in stable condensed ring systems. Elimination of ArH and ArCHO subsequent to the loss of NH 3 and formation of aroyl ion are characteristic decomposition pathways of the [MNH 4 ] + ions, whereas elimination of ArCH 3 and formation of [ArCH 2 ] + are characteristic of the [M + 2H + NH 4 ] + ions of these propenones.