An Ionic Liquid State Composed of Superoxide Radical Anions and Crownether-Coordinated Potassium Cations
An Ionic Liquid State Composed of Superoxide Radical Anions and Crownether-Coordinated Potassium Cations
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由超氧自由基阴离子和冠醚配位钾阳离子组成的离子液体状态
DOI：
10.1149/2.0131708jes
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发表时间：
2017
影响因子：
3.9
通讯作者：
and Kuniaki Murase
中科院分区：
文献类型：
--
作者：
Atsushi Kitada,Daisuke Ishikawa;Kazuhiro Fukami;and Kuniaki Murase
报道了一种由超氧阴离子(O2-−)和冠醚配位的钾阳离子组成的“离子液体”物质。18-冠-6-醚(18C6)和过氧钾(KO2)的二元混合物在38℃以上变成液体，拉曼光谱测量证实了18C6与K+的配位和O2−的存在。在38℃以下，由于K+和18C6之间的离子-离子相互作用被K+和O2−之间的离子-离子相互作用所淹没，18C6-KO2混合物并不形成络合物，而是与固体18C6和KO2的母相发生相分离。也就是说，O2−和18C6配位的K+只出现在纯18C6的熔点以上，形成离子液体状态。在含有自由基的离子液体中，液体18C6-KO2混合物具有较高的流动性和相当的导电性。研究结果表明，高浓度的超氧阴离子在液体状态下稳定，可用于多种自由基反应。
We report an" ionic liquid state" substance composed of superoxide radical anions (O 2−) and crownether-coordinated potassium cations. A binary mixture of 18-crown-6-ether (18C6) and potassium superoxide (KO 2) becomes liquid above ca. 38 C. The coordination of 18C6 to K+ and the presence of O 2− were confirmed in the liquid state by Raman spectroscopy measurements. Below 38 C, however, the 18C6-KO 2 mixture does not form a complex but undergoes phase separation to parent phases of solid 18C6 and KO 2, because the ion-dipole interaction between K+ and 18C6 is overwhelmed by the ion-ion interaction between K+ and O 2−. In other words, the pair of O 2− and 18C6-coordinated K+ only appears above the melting point of pure 18C6, to form an" ionic liquid state". Among radical-containing ionic liquids, the liquid 18C6-KO 2 mixture has high fluidity and comparable conductivity. The findings show stabilization of superoxide radical anions at liquid state with high concentration, which could be used for many radical reactions.