Elimination of difluorocarbene from the molecular ions of alpha, alpha,alpha-trifluorocresols with a fluorine atom migration in an ion trap mass spectrometer.
The elimination of difluorocarbene (CF(2)) from the molecular ions of m-alpha,alpha,alpha-trifluorocresol (MW 162, 1) and p-alpha, alpha, alpha-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 three-membered 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).
Chemistry and Materials Science, Gunma National College of Technology, Maebashi, Gunma, Japan.
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Tajima
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Takahashi
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Sekiguchi
D003408:Cresols / Q000737:chemistry*; D005461:Fluorine / Q000737:chemistry; D017611:Fluorine Compounds / Q000737:chemistry*; D006838:Hydrocarbons; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry
C121083:3-trifluoromethylphenol; D003408:Cresols; D017611:Fluorine Compounds; D006838:Hydrocarbons; D006845:Hydrocarbons, Fluorinated; C121084:difluorocarbene; C030011:carbene; D005461:Fluorine; D008697:Methane