Potentiometric Determination of Stability Constants of Trivalent Metal Ion Complexes with Di-p-tolyl-thiovioluric Acid

1976 ◽  
Vol 31 (8) ◽  
pp. 1096-1098 ◽  
Author(s):  
Pavan Mathur ◽  
D. P. Goel ◽  
R. P. Singh
Keyword(s):  
Stability Constants ◽  
Atomic Number ◽  
Metal Ion ◽  
Formation Constants ◽  
Potentiometric Determination ◽  
Trivalent Metal ◽  
Ionic Radii ◽  
Metal Ion Complexes

The consecutive formation constants of 1:1, 2:1, 3:1 chelate species formed by the interaction of di-p-tolyl-thiovioluric acid (D-p-TOTVA) with the tripositive lanthanons and yttrium cations were determined potentiometrically at 0.1 µ (NaClO4) at 30± 1°C, in 75% aqueous dioxan.The 1:1 formation constants (log K1) for the complexes increase with the increase in the atomic number of the lanthanon (3), with a break at gadolinium.The results indicate that the ligand bonds bidentately to heavier lanthanons (smaller ionic radii). However, definite dentate character of bonding to lighter (larger ionic radii) lanthanons could not be established.

scholarly journals Stability Constants of Some Biologically Important Pyrazoles and Their Ni2+Complexes in Different Dielectric Constant of Medium

2012 ◽  
Vol 9 (2) ◽  
pp. 637-641 ◽  
Author(s):  
S. D. Deosarkar ◽  
A. L. Puyad ◽  
S. A. Chavan
Keyword(s):  
Dielectric Constant ◽  
Ionic Strength ◽  
Stability Constants ◽  
Metal Ion ◽  
Formation Constants ◽  
Water Mixture ◽  
Electrostatic Forces ◽  
Ph Titration ◽  
Titration Technique

The proton-ligand stability constants of some biologically important new pyrazoles and formation constants of their complexes with Ni(II) were determined at 0.1 mol dm-3ionic strength and at 303.15 K in different dielectric constant of dioxane-water mixture by potentiometric method. The Calvin-Bjerrum's pH-titration technique as used by Irving and Rossotti was used for determination of stability constants. The results enabled to study the electrostatic forces of attraction between metal ion and ligand with changes in dielectric constant of the medium.

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