Investigation of carbon-2 substituted imidazoles and their corresponding ionic liquids
作者:Chen Liao、Xiang Zhu、Xiao-Guang Sun、Sheng Dai
DOI:10.1016/j.tetlet.2011.08.010
日期:2011.10
The functionality at the C-2 position of the imidazole ring plays a key role in defining the chemical properties of the imidazoles and their corresponding ionic liquids. Imidazoles 1-6 with different C-2 functionality were synthesized and their corresponding ionic liquids were systematically investigated. Based on their physical properties the six imidazoles can be divided into three groups. (1) The imidazoles 2 and 3 are capable of self-polymerization to form poly(ionic liquid)s, and they are characterized with a strong leaving group at the C-2 position. (2) The imidazoles 4 and 5 can form ionic liquids, but they are very sensitive to moisture. (3) The imidazoles 1 and 6 can form stable ionic liquids, and their stabilities were influenced by the electronic effects of the substituents at the C-2 position. Published by Elsevier Ltd.
Physicochemical properties of imidazolium-derived ionic liquids with different C-2 substitutions
作者:Chen Liao、Nan Shao、Kee Sung Han、Xiao-Guang Sun、De-En Jiang、Edward W. Hagaman、Sheng Dai
DOI:10.1039/c1cp22375e
日期:——
functional groups at the C-2 position generally increased the viscosity and lowered the ionic conductivity. The introduction of an ether group (–CH2OCH2CH2CH2CH3) at the C-2 position not only enhanced the reduction stability of the ionic liquids but also exhibited the lowest solid electrolyte interfacial resistance (RSEI). In contrast, the introduction of a cyano group (–CN) at the C-2 position not only decreased
合成了五种基于C-2取代的咪唑鎓阳离子和双(三氟甲磺酰基)酰亚胺(TFSI)阴离子的室温离子液体,其理化性质为:热性质,密度,粘度,离子电导率,自扩散系数和电化学稳定性。系统地调查。这些离子液体的粘度和离子电导率对温度的依赖性可以通过Vogel-Fulcher-Tamman(VFT)方程来描述。与参比的1-丙基-3-甲基咪唑双(三氟甲磺酰基)酰亚胺相比,在C-2位置引入官能团通常会增加粘度并降低离子电导率。醚基(–CH 2 OCH 2 CH 2 CH在C-2位置的2 CH 3)不仅增强了离子液体的还原稳定性,而且表现出最低的固体电解质界面电阻( R SEI)。相反,在C-2位置引入氰基(–CN)不仅降低了还原稳定性,而且不利地提高了SEI抗性。C-2取代对还原稳定性的影响通过最低未占据分子轨道的能级变化来解释。通过脉冲场梯度核磁共振(PFG-NMR)测量每个离子的自扩散系数( D)。锂转移数(