Phonon-like Hydrogen-Bond Modes in Protic Ionic Liquids.
Phonon-like Hydrogen-Bond Modes in Protic Ionic Liquids.
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DOI：
10.1021/jacs.7b03036
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发表时间：
2017-05
影响因子：
15
通讯作者：
J. Reichenbach;Stuart A Ruddell;Mario González-Jiménez;Julio Lemes;D. Turton;David J. France;K. Wynne
中科院分区：
文献类型：
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作者：
J. Reichenbach;Stuart A Ruddell;Mario González-Jiménez;Julio Lemes;D. Turton;David J. France;K. Wynne
千兆赫到太赫兹频率的红外和拉曼光谱包含了大量关于离子液体的结构、分子间力和动力学的信息。然而，这些光谱通常有大量的贡献，从慢扩散模式到欠阻尼振动和分子内振动模式。这使得很难隔离的作用，如库仑和氢键相互作用的作用。我们已经应用了远红外和超快光学克尔效应光谱仔细选择的离子具有或多或少的对称度，以隔离感兴趣的光谱信号。这使我们能够证明存在的纵向和横向光学声子模式和一个很大的相似性烷基铵基质子离子液体的液体水。数据表明，这种声子模式将存在于所有的离子液体，需要重新解释其光谱。
Gigahertz- to terahertz-frequency infrared and Raman spectra contain a wealth of information concerning the structure, intermolecular forces, and dynamics of ionic liquids. However, these spectra generally have a large number of contributions ranging from slow diffusional modes to underdamped librations and intramolecular vibrational modes. This makes it difficult to isolate effects such as the role of Coulombic and hydrogen-bonding interactions. We have applied far-infrared and ultrafast optical Kerr effect spectroscopies on carefully selected ions with a greater or lesser degree of symmetry in order to isolate spectral signals of interest. This has allowed us to demonstrate the presence of longitudinal and transverse optical phonon modes and a great similarity of alkylammonium-based protic ionic liquids to liquid water. The data show that such phonon modes will be present in all ionic liquids, requiring a reinterpretation of their spectra.