Elimination of difluorocarbene from the molecular ions of α,α,α-Trifluorocresols with a fluorine atom migration in an ion trap mass spectrometer
✍ Scribed by Susumu Tajima; Shinya Takahashi; Osamu Sekiguchi
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 77 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0951-4198
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✦ Synopsis
The elimination of difluorocarbene (CF 2 ) from the molecular ions of m-a,a,a-trifluorocresol (MW 162, 1) and p-a, a, a-trifluorocresol (MW 162, 2) upon electron impact have been investigated using a quadrupole ion trap mass spectrometer. This reaction involves a fluorine (F) atom migration from the trifluoromethyl group to the benzene ring. In the case of 1, an F atom migrates via a four-membered ring transition state to give rise to the molecular ion of p-fluorophenol (MW 112, 5) and a small amount of o-fluorophenol (MW 112, 3). On the other hand, in the case of 2, an F atom migrates to the ipso position of the benzene ring via a threemembered ring transition state to give rise to 5 . These conclusions were confirmed by the comparison of the energy-resolved mass spectra (collision-induced dissociation (CID) spectra versus collision energy) of the m/z 112 ions from 1 and 2 with those of reference compounds, o-, m-and p-fluorophenol (3-5).