Syntheses, structures and properties of 1-ethyl-3-methylimidazolium salts of fluorocomplex anions
Syntheses, structures and properties of 1-ethyl-3-methylimidazolium salts of fluorocomplex anions
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DOI：
10.1039/b310162b
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发表时间：
2004-01-01
影响因子：
4
通讯作者：
Matsubara, S
中科院分区：
文献类型：
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作者：
Matsumoto, K;Hagiwara, R;Matsubara, S
研究了室温离子液体1-乙基-3-甲基咪唑鎓氟化物（EMIm（HF））的氟酸碱反应（2.3）F，EMIm = 1-乙基-3-甲基咪唑鎓阳离子）和刘易斯氟酸（BF 3、PF 5、AsF 5、NbF 5、TaF 5和WF 6）得到相应的氟络合物阴离子的EMIm盐，EMImBF（4）、EMImPF（6）、EMImAsF（6）、EMImNbF（6）、EMImTaF（6）和EMImWF（7），分别由于五价钒的强氧化能力，通过EMIm（HF）（2.3）F与VF 5的酸碱反应和EMImCl与KVF 6的复分解来制备EMImVF（6）的尝试均失败，而EMImSbF（6）仅通过EMImCl和KSbF 6的复分解成功制备。EMImBF（4）、EMImSbF（6）、EMImNbF（6）、EMImTaF（6）和EMImWF（7）在室温下是液体，而EMImPF（6）和EMImAsF（6）在约330 K下熔化。所得盐的拉曼光谱表明存在EMIm阳离子和相应的氟络阴离子。红外光谱表明，在这些盐中没有观察到强氢键。EMImAsF（6）（mp 326 K）和EMImSbF（6）（mp 283 K）与先前报道的EMImPF（6）是同构的。六氟配合物EMIm盐的熔点随阴离子尺寸的增大而降低（PF 6- <AsF 6- <SbF 6- <NbF 6-近似于TaF 6-）。
Fluoroacid - base reactions of a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium fluorohydrogenate (EMIm(HF)(2.3)F, EMIm = 1-ethyl-3-methylimidazolium cation), and Lewis fluoroacids (BF3, PF5, AsF5, NbF5, TaF5 and WF6) give EMIm salts of the corresponding fluorocomplex anions, EMImBF(4), EMImPF(6), EMImAsF(6), EMImNbF(6), EMImTaF(6) and EMImWF(7), respectively. Attempts to prepare EMImVF(6) by both the acid - base reaction of EMIm(HF)(2.3)F with VF5 and the metathesis of EMImCl with KVF6 failed due to the strong oxidizing power of the pentavalent vanadium, whereas EMImSbF(6) was successfully prepared only by the metathesis of EMImCl and KSbF6. EMImBF(4), EMImSbF(6), EMImNbF(6), EMImTaF(6) and EMImWF(7) are liquids at room temperature whereas EMImPF(6) and EMImAsF(6) 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. EMImAsF(6) (mp 326 K) and EMImSbF(6) (mp 283 K) are isostructural with the previously reported EMImPF(6). The melting point of the hexafluorocomplex EMIm salt decreases with the increase of the size of the anion (PF6- < AsF6- < SbF6- < NbF6- approximate to TaF6-).