Identification of 1,3-dialkylimidazolium salt supramolecular aggregates in solution
Identification of 1,3-dialkylimidazolium salt supramolecular aggregates in solution
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DOI：
10.1021/jp0452709
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发表时间：
2005-03-17
影响因子：
3.3
通讯作者：
Dupont, J
中科院分区：
文献类型：
--
作者：
Consorti, CS;Suarez, PAZ;Dupont, J
用X-射线衍射仪研究了1，3-二烷基咪唑阳离子与非配位阴离子如四氟硼酸盐、六氟磷酸根和四苯基硼酸根在固体和溶液中的相互作用。在固体状态下，这些化合物表现出一个扩展的氢键阳离子和阴离子网络，其中一个阳离子被至少三个阴离子包围，一个阴离子被至少三个咪唑基阳离子包围。在纯形式中，咪唑盐更好地描述为通过咪唑阳离子与阴离子的氢键形成的{[(DAI)(3)(X)](2+)[(DAI)(X)(3)](2-)}(N)类型的聚合物超分子(其中DAI是二烷基咪唑阳离子，X是阴离子)。在溶液中，至少在低介电常数的溶剂中，这种超分子结构保持了很大程度，这表明咪唑离子液体与其他分子的混合物可以被认为是纳米结构材料。该模型对于解释大多数离子液体的反常行为是非常有用的。
The nature of the interactions between 1,3-dialkylimidazolium cations and noncoordinating anions such as tetrafluoroborate, hexafluorophosphate, and tetraphenylborate has been studied in the solid state by X-ray diffraction analysis and in solution by H-1 NMR spectroscopy, conductivity, and microcalorimetry. In the solid state, these compounds show an extended network of hydrogen-bonded cations and anions in which one cation is surrounded by at least three anions and one anion is surrounded by at least three imidazoliurn cations. In the pure form, imidazolium salts are better described as polymeric supramolecules of the type {[(DAI)(3)(X)](2+)[(DAI)(X)(3)](2-)}(n) (where DAI is the dialkylimidazolium cation and X is the anion) formed through hydrogen bonds of the imidazolium cation with the anion. In solution, this supramolecular structural organization is maintained to a great extent, at least in solvents of low dielectric constant, indicating that mixtures of imidazolium ionic liquids with other molecules can be considered as nanostructured materials. This model is very useful for the rationalization of the majority of the unusual behavior of the ionic liquids.