Gold(I) cysteinate complexes in aqueous solutions
- Authors: Mironov I.V.1,2, Kharlamova V.Y.1,2
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Affiliations:
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch
- Novosibirsk National Research State University
- Issue: Vol 62, No 7 (2017)
- Pages: 1014-1020
- Section: Physical Chemistry of Solutions
- URL: https://journal-vniispk.ru/0036-0236/article/view/167893
- DOI: https://doi.org/10.1134/S0036023617070154
- ID: 167893
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Abstract
Equilibria between gold(I) cysteinate complexes in aqueous solutions are studied by pH-metry, solubility measurements, and potentiometric measurements using a gold electrode at 25°C and I = 0.2 M (NaCl). The stepwise protonation constants logKiH of cysteinate Hi – 1Cysi – 3 + H+ = HiCysi – 2 are as follows: 10.10 (i = 1), 8.12 (i = 2), and 1.90 (i = 3). Protonation of cysteinate complexes is studied: Au(Cys)23− + H+ = Au(HCys)(Cys)2–, logK1H Au = 9.62 and Au(HCys)(Cys)2– + H+ = Au(HCys)2−, logK2HAu = 9.01. The constant KS of the heterogeneous equilibrium Au(HCys)s + HCys– = Au(HCys)2− is 3.3. The standard potential of the Au(Cys)23− complex is E1/00 = –0.172 ± 0.011 V. The stability of the Au(HCys)2− complex is close to that of Au(HS)2−. The constant of substitution Au(HCys)2− + SO32− = Au(HCys)SO32− + HCys– is determined to be logK11H = –1.3.
About the authors
I. V. Mironov
Nikolaev Institute of Inorganic Chemistry, Siberian Branch; Novosibirsk National Research State University
Author for correspondence.
Email: imir@niic.nsc.ru
Russian Federation, Novosibirsk, 630090; Novosibirsk, 630090
V. Yu. Kharlamova
Nikolaev Institute of Inorganic Chemistry, Siberian Branch; Novosibirsk National Research State University
Email: imir@niic.nsc.ru
Russian Federation, Novosibirsk, 630090; Novosibirsk, 630090
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