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Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions
Author(s) -
Räisänen Minna,
Heliövaara Eeva,
AlQaisi Feda'a,
Muuronen Mikko,
Eronen Aleksi,
Liljeqvist Henri,
Nieger Martin,
Kemell Marianna,
Moslova Karina,
Hämäläinen Jani,
Lagerblom Kalle,
Repo Timo
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201810447
Subject(s) - dissolution , chemistry , pyridine , inorganic chemistry , sulfur , hydrogen peroxide , ligand (biochemistry) , isomerization , sulfuric acid , organic chemistry , catalysis , biochemistry , receptor
Dissolution of elemental gold in organic solutions is a contemporary approach to lower the environmental burden associated with gold recycling. Herein, we describe fundamental studies on a highly efficient method for the dissolution of elemental Au that is based on DMF solutions containing pyridine‐4‐thiol (4‐PSH) as a reactive ligand and hydrogen peroxide as an oxidant. Dissolution of Au proceeds through several elementary steps: isomerization of 4‐PSH to pyridine‐4‐thione (4‐PS), coordination with Au 0 , and then oxidation of the Au 0 thione species to Au I simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is a Au I complex bearing two 4‐PS ligands and SO 4 2− as a counterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.