Interaction of the Bipyridyl Gold(III) Complex with Anions of Thiol-Containing Acids in Aqueous Solution

• Published in: Russian journal of inorganic chemistry Vol. 68; no. 3; pp. 287 - 293
• Main Authors: Mironov, I. V., Kharlamova, V. Yu, Hu, J.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2023; Springer Nature B.V
• Subjects: Anions; Aqueous solutions; Chemistry; Chemistry and Materials Science; Glutathione; Gold; Inorganic Chemistry; Physical Chemistry of Solutions; Reduction; Ultraviolet spectra; thiomalate; nitrogen-containing ligands; complexation; glutathione; cysteine
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023622602422

The equilibria of stepwise substitution Au(bipy) + OH – = Au(bipy)ClOH + + Cl – and Au(bipy) + 2OH – = Au(bipy) + 2Cl – in aqueous solution at T = 25°C and I = 0.2 M (NaCl), log β 1  = 9.22, log β 2 = 16.61 have been studied. For bipyridyl complexes Au(bipy) (X = Cl, OH) at pH 2.0 and 7.4, redox interactions with anions of thiol-containing acids (glutathione, cysteine, thiomalate) have been studied. In all cases, at the initial stage, a rapid reduction of gold(III) to gold(I) was observed with the simultaneous release of bipyridyl. A detailed analysis of UV spectra showed that the main products of gold(III) reduction are highly stable gold(I) thiolate complexes. The presence of further slower steps depends on the initial ratio of thiol to gold.