1155-37-9Relevant academic research and scientific papers
Cooperative Ligands in Dissolution of Gold
Eronen, Aleksi,Heli?vaara, Eeva,Liljeqvist, Henri,Moslova, Karina,Muuronen, Mikko,Repo, Timo
supporting information, (2021/05/19)
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 Au0 that can be oxidized, whereas the role of inexpensive 2-mercaptobenzimidazole is to stabilize the formed AuI 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.
Pyridinethiol-Assisted Dissolution of Elemental Gold in Organic Solutions
R?is?nen, Minna,Heli?vaara, Eeva,Al-Qaisi, Feda'a,Muuronen, Mikko,Eronen, Aleksi,Liljeqvist, Henri,Nieger, Martin,Kemell, Marianna,Moslova, Karina,H?m?l?inen, Jani,Lagerblom, Kalle,Repo, Timo
supporting information, p. 17104 - 17109 (2018/12/04)
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 Au0, and then oxidation of the Au0 thione species to AuI simultaneously with oxidation of free pyridine thione to elemental sulfur and further to sulfuric acid. The final dissolution product is a AuI complex bearing two 4-PS ligands and SO42? as a counterion. The ligand is crucial as it assists the oxidation process and stabilizes and solubilizes the formed Au cations.
Photochemistry of Pesticides, 12. On the Photoconversion of 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, and 2-Chlorobenzothiazole
Abdou, W. M.,Sidky, M. M.,Wamhoff, H.
, p. 1153 - 1158 (2007/10/02)
The photoreactivity of 1,3-dihydro-2-benzimidazole-2-thione (1a) and 2(3)-benzothiazolethione (1b) has been studied in several solvents in the presence of oxygen with or without methylene blue as a sensitizer.The corresponding disulfides (5a, b), 2-oxo derivatives (2a, b), benzimidazole and benzothiazole (11a, b), and elemental sulfur have been characterized as the main products.The UV irradiation of the disulfides 5a, b results in the formation of the same product pattern as the thiones 1a, b.Photolysis of 2-chlorobenzothiazole (12) in acetonitrile gives a mixture of 2b, 2,2'-dibenzothiazole (13), while photolysis of 12 in ethanol yields 2b and 11b.Products and mechanisms are discussed and compared with previous studies in this area. - Key words: 1,3-Dihydro-2-benzimidazole-2-thione, 2(3)-Benzothiazolethione, 2-Chlorobenzothiazole, Photodegradation, Photooxidation
SYNTHESIS OF NEW THIOSULFONATES AND DISULFIDES FROM SULFONYL CHLORIDES AND THIOLS
Mahieu, Jean-Pierre,Gosselet, Martine,Sebille, Bernard,Beuzard, Yves
, p. 1709 - 1722 (2007/10/02)
Aromatic thiols were converted into thiosulfonates or disulfides, under very mild conditions, with fair to excellent yields, by using sulfonyl chloride as oxydant reagent.
