Solution Studies of a Water-Stable, Trivalent Antimony Pnictogen Bonding Anion Receptor with High Binding Affinities for CN-, OCN-, and OAc-

A water-stablebidentate pnictogen bond donor has been evaluatedfor anion binding. It demonstrates very high binding affinities forcyanide, cyanate, and acetate. Density functional theory calculationsreveal a perfect fit for the carboxylate group. This opens up theuse of this pnictogen bond donor motif for anion recognition and noncovalentcatalysis. The solution phase anion bindingbehavior of a water-stablebidentatepnictogen bond donor was studied. A modest change in the visible absorptionspectrum allowed for the determination of the binding constants. Highbinding constants were observed with cyanide, cyanate, and acetate,and these were corroborated with density functional theory (DFT) calculations.The receptor could be recovered free from the anion following treatmentwith methyl triflate, confirming that it remains intact. The tightbinding of cyanide and water stability were exploited to use thissystem as a supramolecular catalyst in a phase-transfer Strecker reaction,further demonstrating the utility of pnictogen bonding as a tool innoncovalent catalysis.

Automated summary

A water-stable bidentate pnictogen bond donor has been found to have high binding affinities for cyanide, cyanate, and acetate. This opens up possibilities for anion recognition and noncovalent catalysis using this pnictogen bond donor motif. The binding behavior of the pnictogen bond donor was studied, and the high binding constants were confirmed through calculations.