Negative ion mass spectra of a series of fluorinated β-diketones

✍ Scribed by I. K. Gregor; K. R. Jennings; D. K. Sen Sharma

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 433 KB
• Volume: 12
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210120209

✦ Synopsis

Abstract

Electron capture by and the subsequent fragmentation of a series of eleven fluorinated β‐diketones of general formula CF~3~COCH~2~COR has been studied in an MS‐50 mass spectrometer. Consecutive loss of two HF molecules from molecular anions occurs with all compounds, as does elimination of CHF~3~ from [M  H]^−^ ions. Elimination of CO occurs from either \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm M - HF}} \right]_{}^{_.^ - } $\end{document} or \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm M - 2HF}} \right]_{}^{_.^ - } $\end{document} ions for five compounds where R  CF~3~ or a cyclic substituent. Kinetic energy release in metastable transitions associated with these HF and CO eliminations has been measured. Intensities of various fragment ions are in part influenced by the ion source temperature. Interaction of \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{{\rm O}} \right]_{}^{_.^ - } $\end{document} reagent ions with five of the β‐diketones under chemical ionization conditions gave [M  H]^−^ ions as the only significant ion‐molecule reaction product.