Gas-phase fluorine migration reactions in the radical cations of pentafluorosulfanylbenzene (Aryl-SF5) and benzenesulfonyl fluoride (Aryl-SO2F) derivatives and in the 2,5-xylylfluoroiodonium ion.

The gas-phase reactions of Aryl-SF5·+ and Aryl-SO2F·+ have been studied with the electron ionization tandem mass spectrometry. Such reactions involve F-atom migration from the S-atom to the aryl group affording the product ion Aryl-F·+ by subsequent expulsion of SF4 or SO2, respectively. Especially, the 4-pentafluorosulfanylphenyl cation 4-SF5C6H4+ ( m/ z 203) from 4-NO2C6H4SF5·+ by loss of ·NO2 could occur multiple F-atom migration reactions to the product ion C6H4F3+ ( m/ z 133) by loss of SF2 in the MS/MS process. The gas-phase reactions of 2,5-xylylfluoroiodonium ( pXyl-I+F, m/ z 251) have also been studied using the electrospray tandem mass spectrometry, which involve a similar F-atom migration process from the I-atom to the aryl group giving the radical cation of 2-fluoro- p-xylene (or its isomer 4-fluoro- m-xylene, m/ z 124) by reductive elimination of an iodine atom. All these gas-phase F-atom migration reactions from the heteroatom to the aryl group led to the aryl-F coupling product ions with a new formed CAryl-F bond. Density functional theory calculations were performed to shed light on the mechanisms of these reactions. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]