Convenient Access to α-Fluorinated Alkylammonium Salts

Area of Science:

• Fluorine Chemistry
• Inorganic Synthesis
• Materials Science

Background:

• Ammonium salts are crucial in various chemical applications.
• Fluorinated organic compounds exhibit unique properties.
• Efficient synthesis of novel fluorinated ammonium salts remains an area of interest.

Purpose of the Study:

• To synthesize novel alpha-fluoroalkyl ammonium salts.
• To explore the reaction of cyano compounds with anhydrous hydrogen fluoride (HF).
• To characterize the resulting fluorinated ammonium salts.

Main Methods:

• Reaction of cyano compounds (BrCN, ClCN, CF3CN, HCF2CN, (CN)2) with anhydrous HF.
• Isolation of salts using counterions like [AsF6](-) and [SbF6](-).
• Characterization using multi-nuclear NMR, vibrational spectroscopy, and X-ray crystallography.

Main Results:

• Successful synthesis of novel alpha-fluoroalkyl ammonium salts.
• Room-temperature stable trifluoromethyl ammonium salts obtained in quantitative yield.
• Characterization confirmed the structures of new cations like [CF3CF2NH3](+), [HCF2CF2NH3](+), and [(NH3CF2)2](2+).
• X-ray crystal structures determined for [HCF2NH3][AsF6] and [CF3NH3][Sb2F11].

Conclusions:

• Anhydrous HF is an effective reagent for synthesizing alpha-fluoroalkyl ammonium salts from nitriles.
• The synthesized salts are stable at room temperature.
• This work expands the library of known fluorinated ammonium compounds with potential applications.