Binding of HgCl2 by a Nitro Functionalized Tripodal Receptor and Its Decomplexation Controlled by Anion Complexation

Abstract

AbstractThe presence of a nitro functionality on N‐bridged tripodal receptors has an effect on its binding ability towards HgCl2 by coordination through one of the nitro oxygen atoms, ethereal oxygen and the bridgehead nitrogen atom. Decomplexation of HgCl2 and recovery of the receptor L can be accomplished by the formation of anion complexes with [L·HgCl2]. The complexation of different anions with multiple protonated receptor units is attributable to intramolecular (N–H)+···anion interactions, at the same time the presence of multiple C–H···anion and interligand C–H···Onitro hydrogen bonds provide added stabilization. Protonation at the bridgehead nitrogen atom and the presence of the nitro functionality render the aliphatic and aryl protons sufficiently acidic for their active participation in moderate to weak C–H···anion and C–H···Onitro interactions. Spectroscopic studies provide evidence for the formation of anion complexes from [L·HgCl2] by extrusion of HgCl2.