Wei Huidan, Wang Yongtao, Yao Jia, Li Haoran
Department of Chemistry, ZJU-NHU United R&D Center, Zhejiang University, Hangzhou, 310027, P. R. China.
Phys Chem Chem Phys. 2018 Feb 7;20(6):4109-4117. doi: 10.1039/c7cp07933h.
The physicochemical properties including melting point, density, viscosity, conductivity, and surface tension as well as spectral properties such as infrared and EPR spectra of the chelate-based ILs [Cmim][Cu(F-acac)] (n = 6, 8, 10, 12, 14) were studied as functions of temperature and chain length. The thermodynamic properties such as the standard molar entropy and crystal energy were estimated by Glasser's theory, the molar enthalpy of vaporization was calculated by Kabo's method, and the ionicity was estimated by the Walden rule. Compared with the common ILs, the chelate-based ILs have larger molecular volume, larger density, smaller crystal energy, poorer ionicity and larger enthalpy of vaporization. The infrared spectra data of the ILs showed a red shift of the C-H bond stretching vibration of the alkyl chain in the cation and the EPR spectra showed that the crystal field of Cu was kept when the chain length was elongated, which indicated the existence of microphase separation in the ILs. This work is helpful in understanding the structure-property relations of chelate-based ILs for further application.
研究了基于螯合物的离子液体[Cmim][Cu(F-acac)]（n = 6、8、10、12、14）的物理化学性质，包括熔点、密度、粘度、电导率和表面张力，以及光谱性质，如红外光谱和电子顺磁共振光谱，它们是温度和链长的函数。通过格拉斯理论估算了标准摩尔熵和晶体能量等热力学性质，通过卡波方法计算了汽化摩尔焓，并通过瓦尔登规则估算了离子性。与普通离子液体相比，基于螯合物的离子液体具有更大的分子体积、更大的密度、更小的晶体能量、更差的离子性和更大的汽化焓。离子液体的红外光谱数据显示阳离子中烷基链的C-H键伸缩振动发生红移，电子顺磁共振光谱表明当链长延长时Cu的晶体场保持不变，这表明离子液体中存在微相分离。这项工作有助于理解基于螯合物的离子液体的结构-性质关系，以便进一步应用。
