Salt-solubilization and ion-pair recognition by a quinoline-substituted crown ether

Abstract

A novel quinoline-substituted crown ether has been synthesized as a receptor for ion pairs and its binding behavior was investigated in various solvents. The binding of ion pairs in [D6]DMSO and in mixed [D 6]DMSO/CD3CN/CDCl3 solvents was studied and the results revealed positive cooperativity effects. As a novel solubilizing agent, the crown ether can extract halide salts into organic media, especially chloride salts. ESI MS provided evidence for the formation of salt-receptor complexes. A recycling experiment showed that the receptor can solubilize salts and can be recovered. This process can be performed as a cycle. This study validates the idea that a straightforward combination of a common anion receptor and a well-studied cation complexation moiety enables the formation of ion-pair receptors and solubilizers of salts in organic solvents. A quinoline- substituted crown ether was synthesized as a novel solubilizing agent for chloride salts and its ion-pair binding and salt-solubilizing properties were investigated. This study validates the idea that a combination of a common anion receptor and a cation complexation moiety enables the formation of ion-pair receptors and solubilizers of salts in organic solvents. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.