Convenient Access to α-Fluorinated Alkylammonium Salts

A series of novel α-fluoroalkyl ammonium salts was obtained from the corresponding cyano compounds or nitriles by reaction with anhydrous HF. Room-temperature stable trifluoromethyl ammonium salts were obtained in quantitative yield in a one-step reaction at ambient temperature from the commercially available starting materials BrCN or ClCN. The novel cations [CF3CF2NH3](+), [HCF2CF2NH3](+), and [(NH3CF2)2](2+) were obtained from CF3CN, HCF2CN, and (CN)2, respectively, and anhydrous HF. The aforementioned fluorinated ammonium cations were isolated as room temperature stable [AsF6](-) and/or [SbF6](-) salts, and characterized by multi-nuclear NMR and vibrational spectroscopy. The salts [HCF2NH3][AsF6] and [CF3NH3][Sb2F11] were characterized by their X-ray crystal structure.