Metal Ion Coordination, Conditional Stability Constants, and Solution Behavior of Chelating Surfactant Metal Complexes

Langmuir ◽  
2014 ◽  
Vol 30 (16) ◽  
pp. 4605-4612 ◽  
Author(s):  
Ida Svanedal ◽  
Susanne Boija ◽  
Ann Almesåker ◽  
Gerd Persson ◽  
Fredrik Andersson ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Stability Constants ◽  
Metal Ion ◽  
Conditional Stability ◽  
Solution Behavior ◽  
Conditional Stability Constants

Can chelation be important in the antiviral activity of isatin β-thiosemicarbazones?

1982 ◽  
Vol 35 (6) ◽  
pp. 1145 ◽  
Author(s):  
H Stunzi
Keyword(s):  
Stability Constants ◽  
Metal Ion ◽  
Copper Ions ◽  
Conditional Stability ◽  
Biologically Relevant ◽  
Cupric Ion ◽  
The Stability ◽  
Conditional Stability Constants ◽  
Metal Ion Chelation

The stability constants of 5-sulfonatoisatin β-thiosemicarbazone (β-thiosemicarbazonoisatin-5- sulfonate) [sibt,(3)] with Zn2+ and Fe2+ have been determined from slow pH titrations (I 0.15M KNO3, 37�). At pH 7.4, the conditional stability constants for the sibt complexes are logK1' 4.5 (Zn2+), 3.1 (Fe2+) and log β2' 8.9 (Zn2+), 6.5 (Fe2+). The mixed ligand complexes Zn(sibt)L (L = histidine or glycine) have conditional stability constants log β1110' 8.8 and 7.0, respectively, at pH 7.4. Copper(I) complexes of sibt and bishistidinato-copper(II) coexist in mixtures of Cu2+, sibt and histidine. [In solutions of copper ions, sibt (complexes Cu+) and histidine (chelates Cu2+), the response of the Orion cupric-ion-selective electrode is not stoichiometric.] Also studied was 1-methyl-5-sulfonatoisatin β-thiosemicarbazone [msibt,(4)] which behaves like sibt. 5-Sulfonatoisatin β-semicarbazone and p-sulfonatobenzaldehyde thiosemicarbazone (p-thiosemicarbazonomethyl- benzenesulfonate) are weak ligands. Comparison of the stability constants with those of complexes of biologically relevant chelating agents showed that isatin β-thiosemicarbazones are not expected to form stable complexes with zinc and iron in vivo. Bidentate thiosemicarbazones, such as benzaldehyde thiosemicarbazones, form even weaker complexes. Both classes of thiosernicarbazones have a similar activity against vaccinia virus; this activity seems not to depend on metal ion chelation.

Fluorescence Analysis of Cu(II), Pb(II) and Hg(II) Ion Binding to Humic and Fulvic Acids

2016 ◽  
Vol 851 ◽  
pp. 135-140 ◽  
Author(s):  
Vojtěch Enev ◽  
Irena Türkeová ◽  
Jana Szewieczková ◽  
Leos Doskocil ◽  
Martina Klučáková
Keyword(s):  
Humic Substances ◽  
Stability Constants ◽  
Metal Ion ◽  
Fluorescence Analysis ◽  
Fulvic Acids ◽  
Ion Binding ◽  
Conditional Stability ◽  
Metal Ion Binding ◽  
The Stability ◽  
Conditional Stability Constants

Abstract. The aim of this work was to study molecular and quantitative aspects of metal ion binding to humic substances (HS). The object of our study was characterization of two standards of humic substances (Elliott Soil standard HA 1S102H and Elliott Soil standard FA 2S102F). All samples of IHSS standards HS were characterized by elemental analysis (EA), ultraviolet-visible spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR) and steady-state fluorescence spectroscopy. Chemical parameters on the complexation of Cu (II), Pb(II) and Hg(II), including the conditional stability constants and the percentage of fluorophores participating in the complexation, were estimated by the modified Stern–Volmer equation. The stability constants (log Ka) of Me(II)–ESHS complexes range from 3.70 to 5.15 in the order: Hg–ESHA>Cu–ESHA>Pb–ESHA>Cu–ESFA>Pb–ESFA. With respect to the ESHA, ESFA, which showed the smallest contents of O-containing functional groups (e.g. hydroxyl, carbonyl, ester, especially carboxyl groups on the aromatic ring) and the lowest humification degree, the ESFA was characterized by much smaller stability constants. Our findings suggest that soil HS belongs to class of important organic ligands for complexation with heavy metal ions and may significantly affect the chemical forms, mobility, bioavailability and ecotoxicity of heavy metals in the soil environment.

Effect of pH, humus concentration and molecular weight on conditional stability constants of cadmium

1988 ◽  
Vol 22 (11) ◽  
pp. 1381-1388 ◽  
Author(s):  
Jan John ◽  
Brit Salbu ◽  
Egil T. Gjessing ◽  
Helge E. Bjørnstad
Keyword(s):  
Molecular Weight ◽  
Stability Constants ◽  
Conditional Stability ◽  
Effect Of Ph ◽  
Conditional Stability Constants
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