Binding and selectivity of dihydrogen phosphate by h-bond donors and acceptors in a tripodal-based thiourea receptor

Abstract

Anion binding properties of a quinoline-based tripodal tris-thiourea receptor have been studied for several oxoanions including perchlorate, nitrate, hydrogen sulfate, and dihydrogen phosphate by H-1 NMR and UV-vis titrations in DMSO. Results show that the receptor selectively binds dihydrogen phosphate with a 1:1 stoichiometry. Ab initio calculations based on density functional theory (DFT) suggest that the dihydrogen phosphate is encapsulated within the host's cavity via six NH center dot center dot center dot O and two N center dot center dot center dot OH interactions.