Improved Access to Organo‐Soluble Di‐ and Tetrafluoridochlorate(I)/(III) Salts

A facile one‐pot gram‐scale synthesis of tetraalkylammonium tetrafluoridochlorate(III) [cat][ClF₄] ([cat]=[NEt₃Me]⁺, [NEt₄]⁺) is described. An acetonitrile solution of the corresponding alkylammonium chloride salt is fluorinated with diluted fluorine at low temperatures. The reaction proceeds via the [ClF₂]^? anion which is structurally characterized for the first time. The potential application of [ClF₄]^? salts as fluorinating agents is evaluated by the reaction with diphenyl disulfide, Ph₂S₂, to pentafluorosulfanyl benzene, PhSF₅. The CN moieties in acetonitrile and [B(CN)₄]^? are transferred in CF₃ groups. Exposure of carbon monoxide, CO, leads to the formation of carbonyl fluoride, COF₂, and elemental gold is dissolved under the formation of tetrafluoridoaurate [AuF₄]^?.