Gao Yan-An, Li Zhong-Hao, Du Ji-Min, Han Bu-Xing, Li Gan-Zuo, Hou Wan-Guo, Shen Dong, Zheng Li-Qiang, Zhang Gao-Yong
Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
Chemistry. 2005 Oct 7;11(20):5875-80. doi: 10.1002/chem.200500120.
The solubilities of beta-cyclodextrin (beta-CD), ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and their mixture in water were determined, and the conductivity of these aqueous solutions was measured. It was demonstrated that beta-CD and bmimPF6 could enhance the solubility of each other, and the solubility curves of each were linear with gradients of about 1. The conductivity decreased remarkably with increasing beta-CD concentration, and a discernible break in the conductivity curve could be observed when beta-CD and bmimPF6 were equimolar in the solution. The solubility and conductivity results indicated that inclusion complexes (ICs) of 1:1 stoichiometry were formed. The inclusion compounds were further characterized by using powder X-ray diffraction (XRD) analysis, 13C CP/MAS (cross-polarization magic-angle spinning) NMR and 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The results showed that the ICs were a fine crystalline powder. The host-guest system exhibited a channel-type structure and each glucose unit of beta-CD was in a similar environment. The decomposition temperature of the ICs was lower than that of bmimPF6 and beta-CD individually.
测定了β-环糊精（β-CD）、离子液体（IL）1-丁基-3-甲基咪唑六氟磷酸盐（bmimPF6）及其混合物在水中的溶解度，并测量了这些水溶液的电导率。结果表明，β-CD和bmimPF6可相互提高溶解度，且各自的溶解度曲线呈线性，斜率约为1。随着β-CD浓度的增加，电导率显著降低，当溶液中β-CD和bmimPF6等摩尔时，可观察到电导率曲线有明显的断点。溶解度和电导率结果表明形成了化学计量比为1:1的包合物（ICs）。通过粉末X射线衍射（XRD）分析、13C CP/MAS（交叉极化魔角旋转）核磁共振和1H核磁共振光谱以及热重分析（TGA）对包合物进行了进一步表征。结果表明，ICs为细结晶粉末。主客体体系呈现通道型结构，β-CD的每个葡萄糖单元处于相似的环境中。ICs的分解温度低于bmimPF6和β-CD单独的分解温度。
