Selective recognition and extraction of arsenate by a urea-functionalized tripodal receptor from competitive aqueous media

Abstract

A second-generation hydrogen bond donor (HBD) anion receptor with an inner amide cavity and an outer urea cavity can selectively and efficiently extract arsenate (AsO43–) from water in the presence...

Cleft Receptor for the Recognition and Extraction of Tetrahedral Oxyanions

“…A significant number of organic receptors are known to bind with sulfate and phosphate anions by employing urea and ortho -bis-urea functional groups. , However, structural evidence of neutral organic receptors recognizing the arsenate anion (AsO 4 3– ) is limited with just two examples before this work. , …”

“…14,37 However, structural evidence of neutral organic receptors recognizing the arsenate anion (AsO 4 3− ) is limited with just two examples before this work. 30,31 Recognition of Sulfate, Phosphate, and Arsenate Anions in Solution State. Having examined the solid-state supramolecular complexes of the three oxyanions with newfound receptor 2, we decided to examine its ability to bind them in solution state with the same stoichiometry.…”

“…18−28 Further, none exists with measured selective affinity for fully deprotonated AsO 4 3− , which is prevalent in oxidizing conditions and high-pH groundwater, 7,29 although a receptor is known to extract it from water. 30 Furthermore, structural evidence for arsenate coordination through hydrogen bonding from charge-neutral organic receptors is still limited with one example for HAsO 4 2− and two examples for AsO 4 3− anions. 22,30,31 Herein, we report the design and synthesis of a readily accessible bis-urea cleft receptor (2, Chart 1) and its anion recognition chemistry with sulfate, phosphate, and arsenate anions.…”

“…30 Furthermore, structural evidence for arsenate coordination through hydrogen bonding from charge-neutral organic receptors is still limited with one example for HAsO 4 2− and two examples for AsO 4 3− anions. 22,30,31 Herein, we report the design and synthesis of a readily accessible bis-urea cleft receptor (2, Chart 1) and its anion recognition chemistry with sulfate, phosphate, and arsenate anions. Our cleft receptor is based on an N,N′-dimethyl-N,N′diphenylurea (1) scaffold.…”

Functionalised polymeric materials for the removal of arsenate from contaminated water

“…While many chemical receptors have been reported for a range of oxyanions (such as phosphate, 14 sulphate 15 and nitrate 16 ), there are very few examples that bind to arsenate. 17–19 In our previous study, 13 we showed that ImpAs-HypoGel adsorbs arsenate with very high capacity and good selectivity over other anions such as sulphate and nitrate. In addition, it can be regenerated and reused easily without loss of performance even after several cycles.…”