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Electron-impact induced fragmentation of partially fluorinated β-diketones |
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| Authors: | M. Rubesch A. L. Clobes M. L. Morris R. D. Koob |
| Affiliation: | 1. Department of Chemistry, North Dakota State University, Fargo, North Dakota 58102, USA National Science Foundation Student Scuience Training Program Participant, 1969.;2. Department of Chemistry, North Dakota State University, Fargo, North Dakota 58102, USA NASA Predoctoral Trainee, 1966 to 69.;3. Department of Chemistry, North Dakota State University, Fargo, North Dakota 58102, USA |
| Abstract: | The ionic fragmentation of twelve partially fluorinated β-diketones, RCOCH2COCF3 was studied with a medium resolution mass spectrometer. In addition to the anticipated fragmentation by β-cleavage, a number of interesting rearrangements are observed. [CF3COCH2CO]+., an ion common to all of the compounds investigated, decomposes predominantly by elimination of HF. When R is an alkyl group containing hydrogen γ to the adgacent carbonyl, the McLafferty rearrangement occurs. The [RCOCH2CO]+.ion eliminates neutral RH when R is phenyl, thienyl, or cyclopropyl. An intense metastable peak, absent when R is an alkyl substituent, accompanies the rearrangement in these three compounds. A number of fragments characteristic of the R substituent are also observed in many cases. This is interpreted as indicating a considerable degree of charge localization on the R moiety. |
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