Generation and Chemistry of Fluorinated Acetoxyl and Oxyallyl Biradical Anions (Distonic Radical Anions) in the Gas Phase

Electron impact on fluorinated acetyl compounds RCOCF3 (R = OH, OSi(CH3)3, OCH3, CF3COCH2, CH3COCH2, CH3, 3,5-(CF3)2C6H3CH2) in an FT-ICR spectrometer yields ionic products of m/z = [M − HF]. These products are proposed to arise via a two-step mechanism:  upon electron impact the neutral precursor gives a fluoride ion−neutral radical complex followed by a secondary reaction of the fluoride anion with the neutral radical, either nucleophilic substitution or proton transfer, to yield a biradical anion (distonic radical anion). These radical anions were isolated and their chemical properties were studied. They undergo reactions characteristic of closed-shell anions, e.g. proton transfer, or characteristic of open-shell species, e.g. radical addition−elimination reactions.