Structures and Properties of 1-Ethyl-3-Methylimidazolium Salts of Fluorocomplex Anions

We have synthesized some room temperature molten salts by the fluoroacid-base reactions of EMIm(HF)2.3F (EMIm: 1-ethyl-3-methylimidazolium) and binary fluorides [4,5]. EMIm(HF)2.3F itself is a room temperature molten salt composed of EMIm cation and (HF)2F and (HF)3F anions which act as fluorobases against Lewis acid fluorides to form the salts containing fluorocomplex anions. EMIm salts of BF4 (m.p.: 288 K), PF6 (m.p.: 333 K), AsF6 (m.p.: 326 K), NbF6 (m.p.: 272 K), TaF6 (m.p.: 275 K), and WF7 (m.p.: 258 K) have been synthesized with this method. The reaction of the obtained EMImWF7 and large excess of H2O gives EMImWOF5. EMImWOF5 is also formed by the reaction of EMIm(HF)2.3F and WOF4. EMImSbF6 (m.p.: 283 K) is synthesized by the reaction of EMImCl and KSbF6.