A new route to the syntheses of N-(fluorosulfuryl)sulfonamide salts: Crystal structure of Ph4P+ [CF3SO2NSO2F]−

A new route for the preparation of potassium and tetraphenylphosphonium salts of N-(fluorosulfuryl)trifluoromethane sulfonamide is described. N-(chlorosulfuryl)-trifluoromethane sulfonamide CF3SO2–NH–SO2Cl, that was used for preparations of both salts, was prepared by the reaction of trifluoromethane sulfonamide CF3SO2NH2 and chlorosulfonic acid in the presence of SOCl2. The obtained N-(chlorosulfuryl)trifluoromethane sulfonamide was converted to potassium N-(fluorosulfuryl)trifluoromethane sulfonamide by using anhydrous KF. Potassium N-(fluorosulfuryl)trifluoromethane sulfonamide served as a starting material for the preparation of the corresponding tetraphenylphosphonium N-(fluorosulfuryl)trifluoromethane sulfonamide that crystallizes from the aqueous solution of potassium N-(fluorosulfuryl)trifluoromethane sulfonamide and tetraphenylphosphonium chloride. N-(fluorosulfuryl)trifluoromethane sulfonamide tetraphenylphosphonium salt is tetragonal, space group P4¯.