Molecular Recognition of Perchlorate Anion With a Cryptand-Based Synthetic Receptor.

Perchlorate anion is a highly toxic environmental contaminant, which is implicated in various health related problems. This paper reports a cryptand-based synthetic molecule (L) prepared from the reaction of tris (2-aminoethyl) amine and 2,5-thiophenedicarboxaldehyde under a high dilution condition, providing a well-defined cavity for a guest species. The hexaprotonated receptor [H₆L]⁶⁺ has been obtained from the addition of six equivalents of tosylic acid to L, which has been studied for perchlorate anion by proton NMR studies in water. The results demonstrate that the receptor strongly binds the negatively charged perchlorate via hydrogen bonding and electrostatic interactions in solution forming a supramolecular anion complex. This molecule can be useful for the future application in the environmental remediation of toxic perchlorate anion.