Fluoroacid–base reactions of a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium fluorohydrogenate (EMIm(HF)2.3F, EMIm = 1-ethyl-3-methylimidazolium cation), and Lewis fluoroacids (BF3, PF5, AsF5, NbF5, TaF5 and WF6) give EMIm salts of the corresponding fluorocomplex anions, EMImBF4, EMImPF6, EMImAsF6, EMImNbF6, EMImTaF6 and EMImWF7, respectively. Attempts to prepare EMImVF6 by both the acid–base reaction of EMIm(HF)2.3F with VF5 and the metathesis of EMImCl with KVF6 failed due to the strong oxidizing power of the pentavalent vanadium, whereas EMImSbF6 was successfully prepared only by the metathesis of EMImCl and KSbF6. EMImBF4, EMImSbF6, EMImNbF6, EMImTaF6 and EMImWF7 are liquids at room temperature whereas EMImPF6 and EMImAsF6 melts at around 330 K. Raman spectra of the obtained salts showed the existence of the EMIm cation and corresponding fluorocomplex anions. IR spectroscopy revealed that strong hydrogen bonds are not observed in these salts. EMImAsF6
(mp 326 K) and EMImSbF6
(mp 283 K) are isostructural with the previously reported EMImPF6. The melting point of the hexafluorocomplex EMIm salt decreases with the increase of the size of the anion (PF6− < AsF6− < SbF6− <="" div="">
常温离子液体1-乙基-3-甲基咪唑鎓氟氢酸盐(EMIm(HF)2.3F,EMIm = 1-乙基-3-甲基咪唑鎓阳离子)与路易斯氟酸(BF3、PF5、AsF5、NbF5、TaF5和WF6)发生氟酸-碱反应,分别生成相应的氟配合阴离子的EMIm盐:EMImBF4、EMImPF6、EMImAsF6、EMImNbF6、EMImTaF6和EMImWF7。尝试通过EMIm(HF)2.3F与VF5的酸碱反应以及EMImCl与KVF6的交换反应制备EMImVF6因五价钒的强氧化性而失败,而EMImSbF6仅通过EMImCl与KSbF6的交换反应成功制备。EMImBF4、EMImSbF6、EMImNbF6、EMImTaF6和EMImWF7在常温下为液体,而EMImPF6和EMImAsF6的熔点在约330 K。所获得盐的拉曼光谱显示存在EMIm阳离子及相应的氟配合阴离子。红外光谱揭示这些盐中未观察到强氢键。EMImAsF6(熔点326 K)和EMImSbF6(熔点283 K)与之前报道的EMImPF6同构。六氟配合物EMIm盐的熔点随阴离子尺寸的增加而降低(PF6− < AsF6− < SbF6− < NbF6− ≈ TaF6−)。