Molecular Interactions of a Cu-Based Metal-Organic Framework with a Confined Imidazolium-Based Ionic Liquid: A Combined Density Functional Theory and Experimental Vibrational Spectroscopy Study
Molecular Interactions of a Cu-Based Metal-Organic Framework with a Confined Imidazolium-Based Ionic Liquid: A Combined Density Functional Theory and Experimental Vibrational Spectroscopy Study
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DOI：
10.1021/acs.jpcc.5b10123
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发表时间：
2016-02-18
影响因子：
3.7
通讯作者：
Kim, Hyung J.
中科院分区：
文献类型：
--
作者：
Dhumal, Nilesh R.;Singh, Manish P.;Kim, Hyung J.
采用密度泛函理论 (DFT) 计算和振动光谱研究了铜基金属有机骨架 (MOP)、Cu-BTC 和离子液体 (IL)、1-乙基-3-甲基咪唑鎓乙基硫酸盐之间的相互作用。傅里叶变换红外（FTIR）和拉曼光谱表明，MOF 中 IL 的限制对 MOF 的结构以及 IL 具有显着影响。拉曼光谱。和 DFT 计算揭示了由于 IL 阴离子与 Cu 离子的相互作用而导致 MOF 结构对称性的扰动。 FTIR 和拉曼光谱表明分子相互作用反过来影响离子对的结构。 MOF 内部形成两种不同类型的 IL 离子对结构。一种离子对结构通过加强阳离子和阴离子之间的氢键而表现出增强的离子间相互作用，而另一种结构对应于IL阳离子和阴离子之间较弱的相互作用。此外，结果表明 IL 咪唑鎓环可以直接与 MOF 或阴离子相互作用。 DFT计算的差电子密度分析表明MOF和IL的分子相互作用伴随着电子密度的转移和重新分布。
The interactions between a Cu-based metal organic framework (MOP), Cu-BTC, and an ionic liquid (IL), 1-ethyl-3-methylimidazolium ethyl sulfate, were studied by employing density functional theory (DFT) calculations and vibrational spectroscopy. The Fourier transform infrared (FTIR) and Raman spectra show that the confinement of the IL in the MOF has significant impact on the structure of the MOF as well as on the IL. Raman spectra. and DFT calculations reveal a perturbation of the symmetry of the MOF structure due to the interaction of the IL anion with the Cu ions. FTIR and Raman spectra show that the molecular interactions in turn influence the structure of the ion pair. Inside the MOF, two different types of structure of IL ion pairs are formed. One ion-pair structure exhibits enhanced interionic interactions by strengthening the hydrogen bonding between cation and anion, whereas the other structure corresponds to weaker interactions between the IL cation and anion. Moreover, it is shown that the IL imidazolium ring can directly interact with either the MOF or the anion. The difference electron density analysis by DFT calculations indicates that molecular interactions of MOF and IL are accompanied by a transfer and redistribution of electron density.