Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• spontaneous complex formation between α-CD and tetrabromoaurate and its current status of use in a few mining sites in the United States. Keywords: bromoaurate; cyanoaurate; cyclodextrin inclusion; self-assembly; supramolecular interactions; Introduction Gold has allured and captivated humankind ever since

• α-CD and cyanoaurate A commonly used step in cyanide leaching is to pass gold-bearing cyanide solutions through activated carbon beds to help concentrate the gold. Following this step, the gold that adsorbed onto carbon is removed either by aggressive solutions (cyanide or hydroxide leaching), or by

• desorption of KAu(CN)2. The ability of α-CD to strip gold from carbon was shown to result from the formation of inclusion complexes directly with the cyanoaurate ions, with (at least) two different stoichiometries of α-CD:KAu(CN)2, 1:1 and 2:2. Structural elucidation was achieved by isolation and X-ray