Comparative Studies on the Complex-Formation Equilibria of Mercury(II) with Acetylcysteine and Captopril
-
H. Köszegi-Szalai
The complex-formation equilibria of mercury(II) with acetylcysteine and captopril have been studied by pH-metric and liquid-liquid extraction methods applying dithizone as a competitive ligand during the latter measurements. The stability constants of three differently protonated Hg(II)/ligand 1:2 complexes of extreme stability have been determined by the combination of extraction and pH-metric data.
The formation of the less stabil Hg(II)-ligand 1:3 complexes with the coordination of three sulfhydrilate groups has been followed and the values of β130/β120 determined from potentiometric measurements.
The differences in the Hg(II) complex formation and protonation equilibria between the two ligands and the possible binding sites in the complexes have been discussed.
Die Komplexbildungsgleichgewichte der Quecksilber(II)-Ionen mit den Liganden Acetylcystein and Captopril wurden mit pH-Metrie und mit einer Extraktionsmethode untersucht. Während der Extraktionen wurde Dithizon als Hilfsligand in der organischen Phase verwendet und die Verteilung des Quecksilbers zwischen den zwei Phasen spektrometrisch gemessen.
Die Komplexstabilitätskonstanten von je drei unterschiedlich protonierten sehr stabilen 1:2-Hg(II)/Ligand-Komplexen wurden mit der Kombination der zwei obengenannten Methoden bestimmt.
Die Bildung von weniger stabilen 1:3-Hg(II)/Ligand-Komplexen bei höheren pH-Werten mit der Koordination durch drei Thiolat-Gruppen wurden mit pH-Metrie geprüft.
Sowohl die Quecksilber(II)-Komplexbildungsgleichgewichte und die Protonierung der zwei Thiol-Liganden als auch die Protonierung der Carboxylat-Gruppen in den 1:2-Komplexen wurden verglichen und die Bindungsstellen der Komplexe eingehend diskutiert.
Articles in the same Issue
- Gibbs Energies of Transfer of Hydrogen Ion from Water to Tetrahydrofuran + Water Mixtures and Basicity and Structuredness of Aquo-ethers
- Gibbs Energy of Transfer of H+ Ion from Water to Urea-Water Mixtures
- Calculation of Gibbs Energies of Hydration of Monovalent Ions: Examination of Born Equation and its Reevaluation
- Comparative Studies on the Complex-Formation Equilibria of Mercury(II) with Acetylcysteine and Captopril
- Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids
- Nonlinear Vibrations in a 2-Dimensional Protein Cluster Model with Linear Bonds
- Electrodeposition of CdSe Films: In-Situ Study by Spectroscopic Ellipsometry
- Elementary Reaction of CF2(X~) with O3: Primary Products
- High-Temperature Carbon Particle Formation and Decay in Carbon Suboxide Pyrolysis behind Shock Waves
Articles in the same Issue
- Gibbs Energies of Transfer of Hydrogen Ion from Water to Tetrahydrofuran + Water Mixtures and Basicity and Structuredness of Aquo-ethers
- Gibbs Energy of Transfer of H+ Ion from Water to Urea-Water Mixtures
- Calculation of Gibbs Energies of Hydration of Monovalent Ions: Examination of Born Equation and its Reevaluation
- Comparative Studies on the Complex-Formation Equilibria of Mercury(II) with Acetylcysteine and Captopril
- Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids
- Nonlinear Vibrations in a 2-Dimensional Protein Cluster Model with Linear Bonds
- Electrodeposition of CdSe Films: In-Situ Study by Spectroscopic Ellipsometry
- Elementary Reaction of CF2(X~) with O3: Primary Products
- High-Temperature Carbon Particle Formation and Decay in Carbon Suboxide Pyrolysis behind Shock Waves
