IR and NMR properties of ionic liquids: do they tell us the same thing?
IR and NMR properties of ionic liquids: do they tell us the same thing?
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DOI：
10.1002/cphc.200700508
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发表时间：
2007-10
期刊：
影响因子：
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通讯作者：
A. Wulf;K. Fumino;D. Michalik;R. Ludwig
中科院分区：
文献类型：
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作者：
A. Wulf;K. Fumino;D. Michalik;R. Ludwig
我们采用理论和实验相结合的方法来推导咪唑类离子液体的光谱性质。振动频率、NMR化学位移和四极耦合常数以可比较的方式对化学环境的变化作出反应。这表明IR和NMR光谱性质都反映了由氢键引起的类似类型的电子扰动。光谱性质的这些关系提供了有关结构复合物的详细信息，因此可以作为离子对形成的良好指标。它们还有助于确定哪种光谱工具对研究分子相互作用最敏感。仅测量一种光谱性质就可以预测其他不那么容易测量的性质。在某些情况下，这是获得可靠的耦合常数的唯一途径，用于从宏观NMR弛豫时间推导分子相关时间，从而为研究离子液体中的结构-动力学关系开辟了新的途径。
We used a combination of theoretical and experimental methods to derive the spectroscopic properties of imidazolium-based ionic liquids. Vibrational frequencies, NMR chemical shifts, and quadrupole coupling constants react in comparable manner to changes in the chemical environment. This suggests that both the IR and the NMR spectroscopic properties reflect a similar type of electronic perturbation caused by hydrogen bonding. These relationships of the spectroscopic properties provide detailed information about structural complexes and may thus serve as good indicators of ion-pair formation. They also help to decide which spectroscopic tool is the most sensitive for investigating molecular interactions. The measurement of only one spectroscopic property allows the prediction of other properties that cannot be so easily measured. In some cases, this is the only way to obtain reliable coupling constants for deriving molecular correlation times from macroscopic NMR relaxation times, thus opening a new path for studying structure-dynamics relations in ionic liquids.