Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Molecules. 2021 May 7;26(9):2751. doi: 10.3390/molecules26092751.
Combining three features-the high affinity of squaramides toward anions, cooperation in ion pair binding and preorganization of the binding domains in the tripodal platform-led to the effective receptor . The lack of at least one of these key elements in the structures of reference receptors and caused a lower affinity towards ion pairs. Receptor was found to form an intramolecular network in wet chloroform, which changed into inorganic-organic associates after contact with ions and allowed salts to be extracted from an aqueous to an organic phase. The disparity in the binding mode of with sulfates and with other monovalent anions led to the selective extraction of extremely hydrated sulfate anions in the presence of more lipophilic salts, thus overcoming the Hofmeister series.
将三种特征结合在一起——席夫碱对阴离子的高亲和力、离子对结合的协同作用以及三齿平台中结合域的预组织——导致了有效受体的形成。参考受体 和 结构中至少缺少这些关键要素中的一个，导致对离子对的亲和力降低。发现受体在湿氯仿中形成分子内网络，与离子接触后变为无机-有机配合物，允许盐从水相萃取到有机相。与硫酸盐以及其他单价阴离子结合模式的差异导致在更亲脂性盐存在的情况下，选择性萃取极其水合的硫酸盐阴离子，从而克服了霍夫迈斯特序列。
