Kinetics of dissociation of ferric chloride complexes. Stability constants of inner- and outer-sphere complexes

1976 ◽  
Vol 80 (25) ◽  
pp. 2801-2804 ◽  
Author(s):  
H. A. Schwarz ◽  
R. W. Dodson
Keyword(s):  
Stability Constants ◽  
Ferric Chloride ◽  
Outer Sphere ◽  
Chloride Complexes ◽  
Kinetics Of ◽  
Outer Sphere Complexes

scholarly journals Ligand substitution kinetics of nickel(II) ion in N,N-dimethylformamide

1977 ◽  
Vol 55 (19) ◽  
pp. 3449-3455 ◽  
Author(s):  
Praphulla Kumar Chattopadhyay ◽  
Byron Kratochvil
Keyword(s):  
Activation Parameters ◽  
Outer Sphere ◽  
Dimethyl Formamide ◽  
Outer Sphere Complex ◽  
Hammett Correlation ◽  
Sphere Complex ◽  
The Stability ◽  
Kinetics Of ◽  
Metal Ligand ◽  
Outer Sphere Complexes

Rate constants and activation parameters for formation of the monocomplexes of Ni(II) ion with several mono-, bi-, and terdentate ligands in N,N-dimethylformamide were obtained by stopped-flow spectrophotometry. The gross features of substitution for all the ligands studied could be accommodated within the structure of an Id-type mechanism. 4-Phenylpyridine behaves most 'normally', and 1,10-phenanthroline stabilized most strongly outer-sphere complex formation with Ni(II). Comparison of these data with previously reported work by other authors for substitution at Ni(II) in acetonitrile with the same ligands indicates that in dimethyl-formamide pyridine-type ligands generally affect the stability of metal–ligand outer-sphere complexes less dramatically than in acetonitrile. Hammett correlation is observed for 1,10-phenanthroline and its 5- and 5,6-substituted derivatives. The slope of the Hammett correlation plot in dimethylformamide is in the order of −0.2, about half the value of −0.4 reported previously in acetonitrile by other authors. This indicates that the stability of the metal–ligand outer-sphere complex is affected more greatly by small differences in the electronic nature of the coordinating substituted 1,10-phenanthrolines in acetonitrile than it is in dimethylformamide.

Kinetic studies on the substitution reactions of (Pyridine-2-carbaldehyde 2'-pyridylhydrazone)nickel(II). A study of stacking interactions in outer-sphere complexes

1980 ◽  
Vol 33 (1) ◽  
pp. 45 ◽  
Author(s):  
RW Renfrew ◽  
P Osvath ◽  
DC Weatherburn
Keyword(s):  
Water Loss ◽  
Kinetic Studies ◽  
Outer Sphere ◽  
Ternary Complexes ◽  
Ring Closure ◽  
Stacking Interactions ◽  
Substitution Reactions ◽  
Loss Mechanism ◽  
Kinetics Of ◽  
Outer Sphere Complexes

Kinetics of the formation reactions of the mono and bis complexes of pyridine-2-carbaldehyde 2'-pyridylhydrazone (paphy) with nickel((II), the mono complex of 6-methylpyridine-2-carbaldehyde2'-pyridylhydrazone (mpaphy) with nickel(II), and of the ternary complexes of Ni(paphy)2+ with terpy, bpy, phen and pada and Ni(paphy)2+ and Ni(phen)2+ with mpaphy have been studied inaqueous solution at 25°C and ionic strength 0.1 mol dm-3 (NaNO3). The rates of the formationreactions of the mono complexes are slower than expected on the basis of the usual water-loss mechanism, and ring closure probably contributes to the observed rates. The formation of the bisand ternary complexes is usually more rapid than predicted by the water-loss mechanism. The enhanced rates are attributed to large outer-sphere association constants due to 'stacking' interactions between the incoming and bound ligands.

Electrode kinetics of Eu3+/Eu2+ reaction by cyclic voltammetry

1982 ◽  
Vol 47 (7) ◽  
pp. 1773-1779 ◽  
Author(s):  
T. P. Radhakrishnan ◽  
A. K. Sundaram
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Outer Sphere ◽  
Electrode Reaction ◽  
Transfer Reactions ◽  
Cyclic Voltammetric ◽  
Edta Solution ◽  
Kinetics Of ◽  
Activated Complex ◽  
Good Agreement

The paper is a detailed study of the cyclic voltammetric behaviour of Eu3+ at HMDE in molar solutions of KCl, KBr, KI, KSCN and in 0.1M-EDTA solution with an indigenously built equipment. The computed values of the rate constants at various scan rates show good agreement with those reported by other electrochemical methods. In addition, the results indicate participation of a bridged activated complex in the electron-transfer step, the rate constants showing the trend SCN- > I- > Br- > Cl- usually observed for bridging order of these anions in homogeneous electron-transfer reactions. The results for Eu-EDTA system, however, indicate involvement of an outer sphere activated complex in the electrode reaction.

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