Hydrogen bonding mediated ion pairs of some aprotic ionic liquids and their structural transition in aqueous solution
Hydrogen bonding mediated ion pairs of some aprotic ionic liquids and their structural transition in aqueous solution
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氢键介导的一些非质子离子液体的离子对及其在水溶液中的结构转变
DOI：
10.1007/s11426-016-0389-4
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发表时间：
2017-03
期刊：
影响因子：
--
通讯作者：
Wang Jianji
中科院分区：
文献类型：
--
作者：
Wang Huiyong;Liu Miao;Zhao Yuling;Xuan Xiaopeng;Zhao Yang;Wang Jianji
离子液体中离子对的形态分布对离子液体的物理化学性质有重要影响，而对溶液中离子对结构的识别至关重要。据报道，某些离子液体的阳离子和阴离子之间可以通过氢键相互作用形成离子对。考虑到远红外（FIR）光谱是表征分子间和分子内氢键的有力工具，在本工作中，将该光谱技术与分子动力学（MD）模拟和核磁共振氢谱（1H NMR）相结合来研究非质子离子液体[Bmim][NO3]，[BuPy][NO3]，[Pyr 14][NO3]，[PP 14][NO3]和[Bu-choline][NO3]在IL水溶液混合物中。的FIR光谱已被指定与密度泛函理论（DFT）计算的帮助下，和结果被用来了解阳离子的性质对离子对的结构的影响。结果发现，在纯非质子离子液体中形成的阳离子和阴离子之间的氢键相互作用的接触离子对，仍然保持在水溶液中高达高的水摩尔分数（说0.80为[BuPy][NO3]）。当水含量增加到水的临界摩尔分数（例如[BuPy][NO3]为0.83）时，由于离子和水之间形成氢键，接触离子对可以转化为溶剂分离的离子对。随着离子液体水溶液的进一步稀释，溶剂分离的离子对最终转化为游离阳离子和游离阴离子（完全水合的阳离子或阴离子）。离子液体的浓度在接触离子对转化为溶剂分离的离子对和溶剂分离的离子对转化为自由离子（完全水合离子）是依赖于阳离子结构。这些信息为质子惰性离子液体在水溶液中的离子对结构提供了直接的光谱证据。分子动力学模拟和1HNMR结果支持了红外光谱研究的结论。
Ion pair speciation of ionic liquids (ILs) has an important effect on the physical and chemical properties of ILs and recognition of the structure of ion pairs in solution is essential. It has been reported that ion pairs of some ILs can be formed by hydrogen bonding interactions between cations and anions of them. Considering the fact that far-IR (FIR) spectroscopy is a powerful tool in indicating the intermolecular and intramolecular hydrogen bonding, in this work, this spectroscopic technique has been combined with molecular dynamic (MD) simulation and nuclear magnetic resonance hydrogen spectroscopy (1H NMR) to investigate ion pairs of aprotic ILs [Bmim][NO3], [BuPy][NO3], [Pyr14][NO3], [PP14][NO3] and [Bu-choline][NO3] in aqueous IL mixtures. The FIR spectra have been assigned with the aid of density functional theory (DFT) calculations, and the results are used to understand the effect of cationic nature on the structure of ion pairs. It is found that contact ion pairs formed in the neat aprotic ILs by hydrogen bonding interactions between cation and anion, were still maintained in aqueous solutions up to high water mole fraction (say 0.80 for [BuPy][NO3]). When water content was increased to a critical mole fraction of water (say 0.83 for [BuPy][NO3]), the contact ion pairs could be transformed into solvent-separated ion pairs due to the formation of the hydrogen bonding between ions and water. With the further dilution of the aqueous ILs solution, the solvent-separated ion pairs was finally turned into free cations and free anions (fully hydrated cations or anions). The concentrations of the ILs at which the contact ion pairs were transformed into solvent-separated ion pairs and solvent-separated ion pairs were transformed into free ions (fully hydrated ion) were dependent on the cationic structures. These information provides direct spectral evidence for ion pair structures of the aprotic ILs in aqueous solution. MD simulation and1H NMR results support the conclusion drawn from FIR spectra investigations.
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影响因子：
3.3
作者：
Consorti, CS;Suarez, PAZ;Dupont, J
通讯作者：
Dupont, J
影响因子：
3.3
作者：
Yaghini, Negin;Pitawala, Jagath;Martinelli, Anna
通讯作者：
Martinelli, Anna
影响因子：
1.2
作者：
N. Scharf;A. Stark;M. Hoffmann
通讯作者：
N. Scharf;A. Stark;M. Hoffmann
DOI：
10.1021/jp076467e
发表时间：
2008-01
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Yang Zhao;Shan Gao;Jianji Wang;Junming Tang
通讯作者：
Yang Zhao;Shan Gao;Jianji Wang;Junming Tang
影响因子：
--
作者：
M. Zanatta;A. Girard;Nathália M. Simon;G. Ebeling;H. Stassen;P. R. Livotto;F. P. dos Santos;J. Dup
通讯作者：
M. Zanatta;A. Girard;Nathália M. Simon;G. Ebeling;H. Stassen;P. R. Livotto;F. P. dos Santos;J. Dup