Highly Efficient and Selective Recognition of Dicyanoaurate(I) by a Bambusuril Macrocycle in Water

Abstract

Abstract Dicyanoaurate(I) anion, [Au(CN) 2 ] − , plays a central role in the current industrial production of gold, as its extraction from crude ore samples represents the most money‐consuming step. Herein, we present the strongest host–guest recognition of dicyanoaurate anion using the bambusuril receptor in water, a highly competitive solvent. The micromolar stability of such a complex facilitated the up to date most efficient supramolecular stripping of dicyanoaurate from activated carbon at ambient temperature. Thermodynamic characteristics of bambusuril binding with [Au(CN) 2 ] − differing from binding of other inorganic chaotropic anions are rationalized, as well as the bambusuril selectivity for [Au(CN) 2 ] − over [Ag(CN) 2 ] − .