Thermodynamic Study of Complexation Phenomena of Some Alkaline Earth Metal (II) Complexes in Propanol‐1‐Water Mixtures at Various Temperatures

Abstract

The stability constants of Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ perchlorates with 2,4-diamino-3,5-dicyanothiophene (DADCT) have been determined at 15, 25, 35, 45 and 55°C in 10, 20 and 30% (w/w) propanol-1-water mixtures using the conductometric technique.The conductometric data were analysed using a model 1:1 stoichiometry by which the stability constants, K s, and the limiting molar conductance were obtained. The plots of specific conductance versus the molar ratio [A] o /[C n+ ] o suggest that the stoichiometry of metal ion complexes is of a 1:1 complex.The stability constants tend to decrease with the atomic number as well as the ionic radii in the order Mg > Ca > Sr > Ba in 10% > 20% > 30% (w/w) propanol-1-water solvents. This trend was found to agree exactly with the Irving-Williams series for all the systems under investigation.The thermodynamic parameters, DG°, DH°and DS°, for the complexation processes of all the complexes were evaluated and their significances were discussed.

Spectrophotometric Study of Complexation Between Some New N2O2‐Schiff Bases and Some Transition Metal Ions in Nonaqueous Solvents

“…We have used the Kinfit and Best program 20,[24][25][26][27] , for evaluating the stability constant of complexes using the spectrophotometric and potentiometric data respectively [28][29][30][31][32] . Of particular interest have been those involving Schiff base since they reveal surprising molecular diversity not only in coordination geometry but in more subtle changes in the ligands.…”

Spectrophotometric Evaluation of Stability Constants of Copper, Cobalt, Nickel and Zinc with 2‐Thiobarbituric Acid in Aqueous Solution

“…Nowadays, different programs such as KINFIT 4 , BEST 5 and DATAN 6 have been used for evaluating the stability constant of complexes or dissociation constant of ligands, using the spectrophotometric or potentiometric data [7][8][9][10][11][12][13][14][15] .…”

Potentiometric and Spectrophotometric Studies of Copper(II) Complexes of Some Ligands in Aqueous and Nonaqueous Solution

“…3 Nowadays different programs such as the KINFIT 4 and BEST 5 programs have been used for evaluating the stability constant of complexes or dissociation constants of ligands, using spectrophotometric or potentiometric data. [6][7][8][9][10][11][12][13][14] Of particular interest have been those involving copper(II) since they reveal surprising molecular diversity not only in coordination geometry but in more subtle changes in the ligands.…”