Selective binding and extraction of aqueous dihydrogen phosphate solutions via three-armed thiourea receptors

Abstract

A series of neutral anion receptors with one to three thiourea arms were synthesized and their binding to tetrabutylammonium chloride, acetate, and dihydrogen phosphate salts in aqueous DMSO mixtures was examined. The three-armed thiourea host was found to strongly and selectively bind H2PO4(-) even in DMSO solutions containing up to 30% water. This enabled the dihydrogen phosphate salt to be extracted from water into chloroform in its dibasic form despite the high heat of the hydration of HPO4(2-).

Anion Binding of One-, Two-, and Three-Armed Thiourea Receptors Examined via Photoelectron Spectroscopy and Quantum Computations

“…Thioureas 1−3 were prepared as previously described. 17 Compound 1 was dissolved in methanol whereas a dimethyl sulfoxide/methanol mixture was used for 2 and 3. These solutions were individually added to separate aqueous methanol mixtures containing NaX, where X = Cl, OAc, and H 2 PO 4 .…”

“…This is different than what is observed in aqueous DMSO solutions where only the binding of H 2 PO 4 − by 3 operates in a cooperative manner and makes use of all three thiourea arms. 17 A single thiourea moiety is used in the other cases, and this indicates that the solvent and/or counterion play a key role and must be responsible for this difference. Dynamics calculations exploring this effect are warranted and would be useful.…”

Bis‐thiourea Derivatives and Their Utility in Synthesis of Mono‐heterocyclic, Bis‐heterocyclic, and Fused Heterocyclic Systems

“…The bis‐thiourea derivative 80 was prepared quantitatively from reaction of the diamine 79 , obtained from palladium‐catalyzed coupling of 2‐pivaloylaminophenylboronic acid 78 and 1,3‐dibromobenzene 77 , with aryl isothiocyanate 4 in THF under nitrogen (Scheme ) .…”

Synthesis and Multi‐Oxo Anion‐Binding Properties of Oligopyrrolic Macrocycles Based on Naphthobipyrrole

“…Multi-oxo anions are of particular relevance in this regard. [9][10][11][12][13][14][15][16][17][18][19][20] For example, a triptycene-derived C 3v -symmetric receptor with anion-binding pyrrole and amide groups was reported by Jurczak et al for the selective recognition of H 2 PO 4 anions. Phosphate anions are acknowledged to affect biological and ecological systems considerably, and a great deal of attention is set on further understanding their impact.…”

“…[8] Thus, phosphate-binding receptors have become an important target in anion-coordination chemistry, and there have been several recent reports of synthetic receptors designed to bind phosphate anions selectively. [9][10][11][12][13][14][15][16][17][18][19][20] For example, a triptycene-derived C 3v -symmetric receptor with anion-binding pyrrole and amide groups was reported by Jurczak et al for the selective recognition of H 2 PO 4 anions. [10] Johnson et al have shown selective recognition of H 2 PO 4 anions over more basic AcOand other anions by an arylethynyl-based bis(urea) receptor.…”