Determination of ion association constants by means of IR absorption band intensities of the molecules forming the first coordination spheres of the cations

1994 ◽  
Vol 50 (4) ◽  
pp. 683-688 ◽  
Author(s):  
L.A. Solovieva ◽  
S.Kh. Akopyan ◽  
E. Vilaseca
Keyword(s):  
Absorption Band ◽  
Ion Association ◽  
Association Constants ◽  
Ir Absorption ◽  
Ion Association Constants ◽  
Coordination Spheres

Octahedral cobalt(III) complexes in dipolar aprotic solvents. VI. Spectrophotometric determination of ion association of halide ions with cis-chlorodimethylformamidebisethylenediaminecobalt(III) ion and cis-chlorobromobisethylenediaminecobalt(III)ion in anhydrous NN-dimethylformamide

1966 ◽  
Vol 19 (6) ◽  
pp. 969 ◽  
Author(s):  
IR Lantzke ◽  
DW Watts
Keyword(s):  
Ion Association ◽  
Cobalt Complexes ◽  
Complex Salt ◽  
Ion Pair ◽  
Association Constants ◽  
Halide Ions ◽  
Kcal Mole ◽  
Ion Association Constants ◽  
Dipolar Aprotic Solvents

Using a spectrophotometric technique the ion association constants for three systems of octahedral cobalt complexes and halide ions have been determined at three temperatures in NN-dimethylformamide. The values of K, ΔH�, and ΔS� for each system have been calculated. At 30� they are as follows: cis-[CoCl(DMF) en2]2+ + Cl- ↔ ion pair K=1.51�0.03 x 104 1.mole-1(ΔH0= 0.93 � 0.02 kcal mole-1,ΔS�= 22.l+0.4 e.u) cis-[CoCl(DMF) en2]2++2Cl- ↔ ion triplet K= 1.21�0.05 X 106 1.2 mole-2(ΔH�=-3.8�0.lkcal mole-1, ΔS�=15.41� 0.5 e.u) cis-[CoCl(DMF) en2]2++Br- ↔ ion pair K= 9.20�0.18 X 103 1.1 mole-1(ΔH�=-7.2�0.lkcal mole-1, ΔS�=42� 1.0 e.u) cis-[CoBrCl en2]+ + Br- ↔ ion pair K = 690�l41. mole-1 (ΔH� = 1.27�0.03 kcal mole-1, ΔS�= 8.8�0.2 e.u.) The dependence of the measured K, the association constant, on the wavelength of measurement, small amounts of water in the solvent, and the anion of the complex salt, has also been investigated.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. III. A new spectrophotometric method for the determination of ion association constants

1966 ◽  
Vol 19 (1) ◽  
pp. 51 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Association Constant ◽  
Ion Association ◽  
Chloride Ion ◽  
Association Constants ◽  
Aprotic Solvents ◽  
Extinction Coefficients ◽  
Ion Association Constants ◽  
Dipolar Aprotic Solvents

A spectrophotometric method for the evaluation of ion association constants has been developed. This method involves the preparation of solutions containing only the compound under consideration. A function relating the association constants to the concentration of compound and extinction coefficients has been derived. The association constants are best determined by an iterative method using a computer. The association constant for the cis-diohlorobisethylenediaminecobalt(111) cation, cis-[Co en2 Cl2]+, and chloride ion in NN-dimethylformamide (DMF) at 30� has been calculated by this new method and is compared with that of another established procedure. The association constant has also been determined for the association of cis-[Co en2 Cl2]+ and iodide in DMF at 30�.

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