Counterion Binding by Polyelectrolytes. III. Stability Constants for the Binding of Univalent Cations by PO3--Groups of Polyphosphates from Electrophoresis Measurements1

1959 ◽  
Vol 81 (20) ◽  
pp. 5295-5298 ◽  
Author(s):  
Ulrich P. Strauss ◽  
Philip D. Ross
Keyword(s):  
Stability Constants ◽  
Univalent Cations ◽  
Counterion Binding

Binding of magnesium and lanthanum ions to heparin in the presence of sodium ions. A relationship between 13C chemical shift displacements and counterion condensation theory

1987 ◽  
Vol 65 (8) ◽  
pp. 1739-1745 ◽  
Author(s):  
Photis Dais ◽  
Qin-Ji Peng ◽  
Arthur S. Perlin
Keyword(s):  
Chemical Shift ◽  
Sodium Ions ◽  
Univalent Cations ◽  
Counterion Condensation ◽  
Ionic Radii ◽  
Counterion Binding ◽  
Binding Preference ◽  
13C Chemical Shift ◽  
Site Binding ◽  
C Nmr

Interactions between beef lung heparin and Mg2+ and La3+ counterions, in the presence of sodium ions, have been investigated by 13C-nmr spectroscopy. The chemical shift displacements observed for the carbons of the main disaccharide unit of heparin, when analysed on the basis of counterion condensation theory, indicate that the association between the heparin polyanion and Mg2+ is a delocalized process. This is analogous to the Ca2+/Na+/heparin system, despite the fact that the binding affinity of heparin for Ca2+ is stronger than that for Mg2+. By contrast, the interaction with La3+ is in excess of the theoretical predicted, which suggests that there is at least a partial site-binding of this counterion. In Ca2+/M+/heparin systems in which M+ = Na+ or K+, the selective binding preference of heparin for the univalent cations may be related to the order of their crystallographic ionic radii. A critical assessment is offered of the validity of this nmr spectroscopic approach to the study of counterion binding to heparin.

Determination of stability constants for complexes from catalytic linear scan voltammetric currents

1998 ◽  
Vol 95 (5) ◽  
pp. 1091-1100 ◽  
Author(s):  
J. L. Muñiz Alvarez ◽  
J. A. García Calzón ◽  
J. M. López Fonseca
Keyword(s):  
Stability Constants

Changes in the Humic Acid–Metal Complexation Characteristics Depending on Humification Degree / Humīnskābju – Metālu Kompleksveidošanās Rakstura Izmaiņas Atkarībā No Humifikācijas Pakāpes

2012 ◽  
Vol 51 (3) ◽  
pp. 228-237
Author(s):  
D. Dudare ◽  
M. Klavins
Keyword(s):  
Humic Acid ◽  
Stability Constants ◽  
Humic Acids ◽  
Complex Stability ◽  
Peat Layer ◽  
Raised Bog ◽  
Complexing Capacity ◽  
Humification Degree ◽  
Complexation Process ◽  
Complex Stability Constants

The aim of this study is to determine the Cu(II) complexing capacity and stability constants of Cu(II) complexes of humic acids isolated from two well-characterized raised bog peat profiles in respect to the basic properties and humification characteristics of the studied peats and their humic acids. The complex stability constants significantly change within the studied bog profiles and are well correlated with the age and decomposition degree of the peat layer from which the humic acids have been isolated. Among factors that influence this complexation process, molecular mass and ability to form micellar structures (supramolecules) of humic substances are of key importance.

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