含酯基吡啶类离子液体的晶体结构及酯基链长微变对其性质的影响

发布时间：2018-04-21 12:06

本文选题：离子液体 + 晶体结构　；参考：《人工晶体学报》2016年06期

【摘要】：基于酯基链长的微小变化,采用两步法设计合成两个含酯基吡啶类离子液体1-乙酸甲酯基-3-甲基吡啶六氟磷酸盐[Me MPy][PF6](记IL1)和1-乙酸乙酯基-3-甲基吡啶六氟磷酸盐[EAMPy][PF6](记IL2)。采用溶剂挥发法在混合溶剂体系中获得6.5 mm IL1和8.0 mm IL2大单晶体,酯基链由乙酸甲酯基微变为乙酸乙酯基,其晶体结构及超分子结构的形成具有显著的变化。晶体学数据研究表明,IL1属于三斜晶系,空间群为P1,其晶胞参数为a=0.8754(3)nm,b=0.8780(3)nm,c=1.0551(6)nm,z=2等。IL2属于正交晶系,空间群为P2(1)2(1)2(1),其晶胞参数为a=0.7127(17)nm,b=1.2792(3)nm,c=1.5327(3)nm,z=4等。随着酯基链的增长,分子结构空间位阻发生了变化,IL2中亚甲基和吡啶环上的甲基均参与超分子空间网络形成,改变了晶体堆积的空间点阵和性质。进一步实验验证表明,酯基链较长的IL2熔点较高,热稳定性较差,然而阳离子结构的微小变化对其离子导电活性的影响相对较小。
[Abstract]:Based on the slight change of ester chain length, two ester containing pyridine ionic liquids, methyl 1-acetate methyl 3-methylpyridine hexafluorophosphate [me MPy] [PF6] and ethyl 1-acetate ethyl -3-methylpyridine hexafluorophosphate [EAMPy] [PF6] were designed and synthesized by two-step method. The large single crystals of 6.5mm IL1 and 8.0mm IL2 were obtained by solvent volatilization in mixed solvent system. The ester chain changed from methyl acetate group to ethyl acetate group. The crystal structure and supramolecular structure of the crystal changed remarkably. The crystallographic data show that the crystal structure and space group are trichroic system, and the cell parameters are a 0.8754 ~ 3nmb ~ (1) ~ (0.8780) ~ (3) nmb ~ (1) C ~ (1.05551) ~ (6) Nm ~ (2) C ~ (2), etc., and the space group is (P212) ~ (12) ~ (2) ~ (1) ~ (1) ~ (1). The unit cell parameter is a ~ (0.7127) ~ (~ (17)) nmb ~ ((1)) ~ (1) 2792nmcn ~ (1) ~ (?) ~ (1) ~ (1) 272727 ~ (3) nmcn ~ (?) ~ (1) ~ (?) ~ (1). With the increase of ester chain, the steric hindrance of molecular structure changes. Both methylene and methyl on pyridine ring participate in the formation of supramolecular space network, which changes the spatial lattice and properties of crystal stacking. Further experiments showed that the IL2 with longer ester chain had higher melting point and poor thermal stability, but the small change of cationic structure had little effect on its ionic conductivity.
【作者单位】：西安工程大学环境与化学工程学院;
【基金】：国家自然科学基金(21573171) 陕西省自然科学基础研究基金项目(2013JQ6010,2016JM5042) 陕西省教育厅专项科研计划项目(12JK0457,16JK1325) 国家级大学生创新创业训练计划(201510709368) 2016年度研究生创新基金(CX201607)
【分类号】：O626.32

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