An Ammonium Solvate Ionic Liquid
An Ammonium Solvate Ionic Liquid
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DOI：
10.1149/1945-7111/abe512
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发表时间：
2021-02
影响因子：
3.9
通讯作者：
Kio Kawata;A. Kitada;Kazuhiro Fukami;Masayuki Saimura;T. Nagata;M. Katahira;K. Murase
中科院分区：
文献类型：
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作者：
Kio Kawata;A. Kitada;Kazuhiro Fukami;Masayuki Saimura;T. Nagata;M. Katahira;K. Murase
报道了第一例铵（NH 4+）溶剂化物离子液体（ILs）.该化合物是铵双（三氟甲基磺酰基）酰胺-18-冠-6（1/1），即[NH 4+][Tf 2 N-]− 18 C6（1/1），其中Tf代表SO 2 CF 3。通过拉曼光谱、核磁共振谱和密度泛函理论计算，证明该化合物是一种铵溶剂化物IL [NH 4+·18 C6][Tf 2N-]，由18 C6配位的NH 4+阳离子和Tf 2N-阴离子组成.铵溶剂化物IL的电导率在150 ℃时高达10 mS cm-1.通过热重分析法证实了低于200 ℃的挥发性可忽略不计。与水合氢离子（H3 O+）溶剂化物IL [H3 O+·18 C6][Tf 2 N-]相比，铵溶剂化物IL显示出更好的热稳定性，这强烈表明18 C6与NH 4+阳离子的停留时间较长。NH 4+离子在18 C6溶剂中的自扩散系数证明了NH 4+离子的稳定性可能导致其在18 C6溶剂中的载体型平移运动。这一发现为设计适用于150 ~ 200 ℃中低温的铵离子电池和燃料电池的新型NH 4+或质子导体提供了指导。
The first example of ammonium (NH 4+) solvate ionic liquids (ILs) is reported. The compound is ammonium bis (trifluoromethylsulfonyl) amide-18-crown-6 (1/1), ie [NH 4+][Tf 2 N–]− 18C6 (1/1), where Tf represents SO 2 CF 3. Raman spectra, NMR spectra, and DFT calculations support the conclusion that the compound can be described as an ammonium solvate IL [NH 4+· 18C6][Tf 2 N–], which consists of 18C6-coordinated NH 4+ cations and Tf 2 N–anions. The conductivity of the ammonium solvate IL reaches as high as 10 mS cm–1 at 150 C. The negligible volatility below 200 C is confirmed by thermogravimetry. Compared with a hydronium (H 3 O+) solvate IL [H 3 O+· 18C6][Tf 2 N–], the ammonium solvate IL shows better thermal stability, which strongly suggests long residence time of 18C6 with NH 4+ cation. The stability may lead to the vehicular-type translational motions of NH 4+ cations with 18C6 solvents as proved by their self-diffusion coefficients. The findings regarding this ammonium solvate IL can provide the guidelines to design new NH 4+ or proton conductors for ammonium ion batteries and fuel cells, which work at medium-low temperatures of 150 C–200 C.