A simple access to metallic or onium bistrifluoromethanesulfonimide salts

Numerous salts of the (CF₃SO₂)₂N⁻ anion, called TFSI, were prepared according to an original one-pot procedure. First, N-benzyl trifluoromethanesulfonimide (N-benzyl triflimide) was treated with ethanol to form an oxonium intermediate, which was then neutralized by various bases to provide metallic or trialkylammonium triflimides salts. Alternatively, N-benzyl triflimide was directly treated with trialkyl sulfonium, quaternary ammonium or phosphonium halides to deliver the corresponding triflimide derivatives. N-Benzyl triflimide can be also reacted with di- or tri-alkylamines and phosphines to get benzyl onium salts. Analogous reactions can be carried out with N-allyl triflimide. Therefore, the TFSI anion can be very easily and expediently associated with a wide range of metallic or organic cations. Such salts can find applications as electrolytes for batteries and fuel cells, ionic liquids or Lewis acids.