Removal of phosphate in presence of interfering sulphate and arsenate by a tripodal thiourea receptor by precipitation through crystallization in semi-aqueous medium

A cyanuric acid platform based tripodal thiourea receptor, L shows encapsulation of phosphate, sulphate and arsenate anions in semi-aqueous medium. Solution phase H-1 NMR showed selective recognition of phosphate anion in presence of various anions (e.g. Cl-, Br-, I-, NO3-, HSO4-, CH3CO2- and H2PO4- as TBA salts) in DMSO-d(6) at 298 K. L showed partial removal and separation of phosphates from semi-aqueous solution in the presence of interfering arsenate and sulphate via precipitation through crystallization. In the absence of phosphate, L is found to remove/separate arsenate from semi-aqueous medium in presence of sulphate which is the first report of partial removal of arsenate from semi-aqueous medium by a neutral anion receptor. In absence of phosphate and arsenate anions, L could partially remove sulphate anions from mixture of other anions from semi-aqueous solution. All the extracted complexes were characterized by NMR, PXRD, TEM-EDX and Single crystal X-Ray diffraction analysis. (C) 2019 Elsevier Ltd. All rights reserved.