Ion-Molecule Reactions in Gaseous CF4/CO Mixtures. Formation and Reactivity of CF3CO(1+) Ions

Article abstract of DOI:10.1021/j100057a017

The reactivity of CF3CO(1+) ions, formed via two different routes, has been studied in the gas phase by the joint use of mass spectrometric and radiolytic techniques, spanning a pressure range from 10^-8 Torr to ca. 1 atm.The 23 kcal mol^-1 exothermic addition of CF3(1+) to CO provides a route to CF3CO(1+) requiring third-body stabilization of the adduct ion.In the 10^-8 Torr pressure regime of Fourier transform ion cyclotron resonance (FT-ICR) spectrometry, CF3CO(1+) ions from electron ionization (EI) induced fragmentation of trifluoroacetic anhydride yield NuCF3(1+) products from oxygen-centered nucleophiles (Nu) and XC6H4CO(1+) ions from aromatics (C6H5X).At ca. 1 atm trifluoroacetylated products are efficiently formed even with strongly deactivated aromatics, showing distinct intra- and intermolecular selectivity features pertaining to the reactant CF3CO(1+) ions.The reactivity pattern is interpreted according to a kinetic interplay of collisional and chemical events depending on the activation of C6H5X toward electrophilic attack.