scholarly journals Cadmium-Imidazole Complex Formation in Aqueous Solutions. Stability Constants, Changes in Standard Free Energies, Enthalpies, Entropies, and Heat Capacities Accompanying the Complex Formation at 5, 15, 25, and 40 degrees C.

1975 ◽  
Vol 29a ◽  
pp. 250-254 ◽  
Author(s):  
Jørgen Birger Jensen ◽  
Erik Grønn Iversen ◽  
Bernt Klewe ◽  
Mats Granberg ◽  
Fred Karlsson ◽  
...  
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Heat Capacities ◽  
Free Energies

The affinity of aldehydic compounds to complex formation. Nickel(II) and cobalt(II) complexes with 2-pyridinecarboxaldehyde

1977 ◽  
Vol 55 (14) ◽  
pp. 2613-2619 ◽  
Author(s):  
M. S. El-Ezaby ◽  
M. A. El-Dessouky ◽  
N. M. Shuaib
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Metal Ion ◽  
Experimental Conditions ◽  
Complex Species ◽  
Spectrophotometric Methods ◽  
Complex Equilibria ◽  
The Stability ◽  
Hydroxy Groups

The interactions of Ni(II) and Co(II) with 2-pyridinecarboxaldehyde have been investigated in aqueous solutions at μ = 0.10 M (KNO3) at 30 °C. The stability constants of different complex equilibria have been determined using potentiometric methods. Spectrophotometric methods were also used in the case of the nickel(II) – 2-pyridinecarboxaldehyde system. It was concluded that nickel(II) and cobalt(II), analogous to copper(II), enhance hyrdation of 2-pyridinecarboxaldehyde prior to deprotonation of one of the geminal hydroxy groups. Complex species of 1:1 as well as 1:2 metal ion to ligand composition exist under the experimental conditions used.

scholarly journals An investigation of the Fe 3+ - sulphonated pyrogallol system in aqueous solutions

2000 ◽  
Vol 65 (4) ◽  
pp. 255-263 ◽  
Author(s):  
M.G. Pjescic ◽  
D.S. Veselinovic ◽  
V.P. Komnenic ◽  
I.V. Draskovic
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Relative Stability ◽  
Ph Value ◽  
Electrochemical Behaviour ◽  
Optimal Ph

The electrochemical behaviour of the Fe 3+ -sulphonated pyrogallol (SP) complex was investigated and its composition and stability constants were determinated at pH 2.30. It was found by voltammetric and spectrophotometric measurements that Fe 3+ and SP form a complex of the ML2 type, which is relatively stable during the first 30 minutes. The optimal pH value for complex formation is between 2.30 and 2.80. The relative stability constants determined by voltammetric and spectrophotometric measurements are log ?2 = 5.08?0.26 and log ?2 = 6.31 ?0.04, respectively.

Heat capacities, self-association and complex formation in alcohol–ester systems

1991 ◽  
Vol 87 (8) ◽  
pp. 1133-1139 ◽  
Author(s):  
Dinkar D. Deshpande ◽  
Donald Patterson ◽  
Lina Andreoli-Ball ◽  
Miguel Costas ◽  
Luis M. Trejo
Keyword(s):  
Complex Formation ◽  
Heat Capacities ◽  
Self Association

Adsorption of sodium cyclododecylmethanoate and cycloundecylmethanoate at the air/water interface

1984 ◽  
Vol 62 (11) ◽  
pp. 2359-2363 ◽  
Author(s):  
Jan J. Spitzer
Keyword(s):  
Aqueous Solutions ◽  
Sodium Ion ◽  
Ion Concentration ◽  
Ionic Surfactants ◽  
Free Energies ◽  
Straight Chain ◽  
Double Chain ◽  
Adsorbed State ◽  
Critical Micelle Concentrations ◽  
Air Water Interface

Surface tension measurements on aqueous solutions of sodium cyclododecylmethanoate and sodium cycloundecylmethanoate in sodium carbonate/bicarbonate buffers and at constant sodium ion concentration at 25 °C were used to obtain the standard free energies of adsorption, the saturation areas per surfactant ion, and the critical "micelle" concentrations of these compounds. Similar measurements were done for solutions of sodium dodecanoate for comparisons.The standard free energies of adsorption of CH2 group that is located in a macrocyclic cycloalkyl ring appears to follow the "rule of two" (−RT ln 2) that is also valid for straight chain ionic surfactants. The saturation areas of both cyclododecylmethanoate and cycloundecylmethanoate are about 52 Å2/ion as compared to about 32 Å2/ion for normal dodecanoate.For large ring cycloalkylmethanoates the critical "micelle" concentrations appear to decrease by a factor of about 4/5 for each CH2 group added to the ring as compared to the factor of about 1/2 for each CH2 group added to the chain of normal alkanoates. The data suggest that large cycloalkyl rings have "collapsed ring", or "double chain", conformation in aqueous solutions and in the adsorbed state.

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