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Cooperative Ligands in Dissolution of Gold
Author(s) -
Heliövaara Eeva,
Liljeqvist Henri,
Muuronen Mikko,
Eronen Aleksi,
Moslova Karina,
Repo Timo
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202101028
Subject(s) - dissolution , thiol , pyridine , ligand (biochemistry) , chemistry , combinatorial chemistry , hydrogen peroxide , catalysis , molecule , inorganic chemistry , nanotechnology , organic chemistry , materials science , receptor , biochemistry
Development of new, environmentally benign dissolution methods for metallic gold is driven by needs in the circular economy. Gold is widely used in consumer electronics, but sustainable and selective dissolution methods for Au are scarce. Herein, we describe a quantitative dissolution of gold in organic solution under mild conditions by using hydrogen peroxide as an oxidant. In the dissolution reaction, two thiol ligands, pyridine‐4‐thiol and 2‐mercaptobenzimidazole, work in a cooperative manner. The mechanistic investigations suggest that two pyridine‐4‐thiol molecules form a complex with Au 0 that can be oxidized, whereas the role of inexpensive 2‐mercaptobenzimidazole is to stabilize the formed Au I species through a ligand exchange process. Under optimized conditions, the reaction proceeds vigorously and gold dissolves quantitatively in two hours. The demonstrated ligand‐exchange mechanism with two thiols allows to drastically reduce the thiol consumption and may lead to even more effective gold dissolution methods in the future.