A non-mulitmacrocyclic ion pair receptor with the ability to cooperatively bind lithium cations and halide anions is presented. These receptors feature a squaramide function for anion binding and are directly linked to a benzo-4-crown-12 unit to achieve selectivity toward lithium salts. Ion pair receptors 1 and 3 demonstrated stronger anion binding in the presence of cobound cations, while anion receptor 2 lacks this property. X-ray measurements supported the simultaneous binding capability of ion pair receptors for both cations and anions. Under solid–liquid extraction (SLE) conditions in acetonitrile, ion pair receptors 1 and 3 selectively extract lithium salts. The more lipophilic receptor 1 can extract LiCl in liquid–liquid extraction (LLE) and SLE, with the latter process notably more selective and effective. Improved LLE extraction of lithium chloride was achieved using copolymer 5 containing receptor units in the structure. The inability of receptor 2 or benzo-12-crown-4 ether to extract salts is attributed to the absence of a heteroditopic binding domain in their structures. This underscores the significant influence of both anion and cation binding domains in the receptor structures on the effective and selective extraction of lithium halide salts. The selectivity of these receptors and the polymeric material toward lithium salts suggests significant potential for extracting lithium from brine solutions with elevated halide content.

中文翻译：

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一种基于方形酰胺-冠醚的受体和聚合物，用于增强氯化锂提取


提出了一种具有协同结合锂阳离子和卤化物阴离子能力的非多环大环离子对受体。这些受体具有用于阴离子结合的方形酰胺功能，并直接与苯并-4-冠-12 单元连接，以实现对锂盐的选择性。离子对受体 1 和 3 在共结合阳离子存在下表现出更强的阴离子结合，而阴离子受体 2 则缺乏这种特性。X 射线测量支持离子对受体对阳离子和阴离子的同时结合能力。在乙腈的固液萃取 （SLE） 条件下，离子对受体 1 和 3 选择性萃取锂盐。亲脂性更强的受体 1 可以在液-液萃取 （LLE） 和 SLE 中提取 LiCl，后者的过程明显更具选择性和有效性。使用结构中含有受体单元的共聚物 5 实现了氯化锂的改进 LLE 提取。受体 2 或苯并-12-冠-4 醚无法提取盐归因于其结构中不存在异位结合结构域。这强调了受体结构中的阴离子和阳离子结合结构域对卤化锂盐的有效和选择性提取的显着影响。这些受体和聚合物材料对锂盐的选择性表明，从卤化物含量较高的盐水溶液中提取锂具有巨大潜力。