Cyclic Voltammetric Evaluation of Rate Constants for Conformational Transitions Accompanying Electron Transfer. Effect of Varying Structural Constraints in Copper(II/I) Complexes with Dicyclohexanediyl-Substituted Macrocyclic Tetrathiaethers

1997 ◽  
Vol 36 (20) ◽  
pp. 4475-4483 ◽  
Author(s):  
Nicole M. Villeneuve ◽  
Ronald R. Schroeder ◽  
L. A. Ochrymowycz ◽  
D. B. Rorabacher
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Conformational Transitions ◽  
Transfer Effect ◽  
Structural Constraints ◽  
Cyclic Voltammetric

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.

The Effect of p-Toluidine on the Two-Step Electroreduction of Zn(II) in Water-Methanol and Water-Dimethylformamide

1999 ◽  
Vol 64 (4) ◽  
pp. 585-594 ◽  
Author(s):  
Barbara Marczewska
Keyword(s):  
Electron Transfer ◽  
Binary Mixtures ◽  
Rate Constant ◽  
Rate Constants ◽  
Electrode Surface ◽  
Mercury Electrode ◽  
Forward Rate ◽  
Solvent Molecules ◽  
Activated Complex

The acceleration effect of p-toluidine on the electroreduction of Zn(II) on the mercury electrode surface in binary mixtures water-methanol and water-dimethylformamide is discussed. The obtained apparent and true forward rate constants of Zn(II) reduction indicate that the rate constant of the first electron transfer increases in the presence of p-toluidine. The acceleration effect may probably be accounted for by the concept of the formation on the mercury electrode an activated complex, presumably composed of p-toluidine and solvent molecules.

A Comparison between Interfacial Electron-Transfer Rate Constants at Metallic and Graphite Electrodes

2006 ◽  
Vol 110 (39) ◽  
pp. 19433-19442 ◽  
Author(s):  
William J. Royea ◽  
Thomas W. Hamann ◽  
Bruce S. Brunschwig ◽  
Nathan S. Lewis
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Transfer Rate ◽  
Interfacial Electron Transfer ◽  
Electron Transfer Rate ◽  
Graphite Electrodes

Reduction of the oxidized bacteriochlorophyll dimer in reaction centers by ferrocene is dependent upon the driving force

2007 ◽  
Vol 11 (03) ◽  
pp. 205-211 ◽  
Author(s):  
László Kálmán ◽  
Arlene L. M. Haffa ◽  
JoAnn C. Williams ◽  
Neal W. Woodbury ◽  
James P. Allen
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Ph Dependence ◽  
Photosynthetic Bacterium ◽  
Energy Difference ◽  
Reaction Centers ◽  
Free Energy Difference ◽  
Midpoint Potential ◽  
Bacteriochlorophyll Dimer ◽  
Purple Photosynthetic Bacterium

The rates of electron transfer from ferrocene to the oxidized bacteriochlorophyll dimer, P , in reaction centers from the purple photosynthetic bacterium Rhodobacter sphaeroides, were measured for a series of mutants in which the P / P + midpoint potentials range from 410 to 765 mV (Lin et al. Proc. Natl. Acad. Sci. USA 1994; 91: 10265-10269). The observed rate constant for each mutant was found to be linearly dependent upon the ferrocene concentration up to 50 μM. The electron transfer is described as a second order reaction with rate constants increasing from 1.5 to 35 × 106 M -1. s -1 with increasing P / P + midpoint potential. This dependence was tested for three additional mutants, each of which exhibits a pH dependence of the P / P + midpoint potential due to an electrostatic interaction with an introduced carboxylic group (Williams et al. Biochemistry 2001; 40: 15403-15407). For these mutants, the pH dependence of the bimolecular rate constants followed a sigmoidal pattern that could be described with a Henderson-Hasselbalch equation, attributable to the change of the free energy difference for the reaction due to deprotonation of the introduced carboxylic side chains.

scholarly journals The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

2021 ◽  
Author(s):  
Karuppasamy Dharmaraj ◽  
Dirk Dattler ◽  
Heike Kahlert ◽  
Uwe Lendeckel ◽  
Felix Nagel ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Transfer Rate ◽  
Chemical Environment ◽  
Lipid Monolayers ◽  
Redox Potentials ◽  
Electron Transfer Rate ◽  
Thermodynamics And Kinetics ◽  
Mercury Electrodes ◽  
Kinetics Of

AbstractThe effects of the chemical environment of menaquinones (all-trans MK-4 and all-trans MK-7) incorporated in lipid monolayers on mercury electrodes have been studied with respect to the thermodynamics and kinetics of their electrochemistry. The chemical environment relates to the composition of lipid films as well as the adjacent aqueous phase. It could be shown that the addition of all-trans MK-4 to TMCL does not change the phase transition temperatures of TMCL. In case of DMPC monolayers, the presence of cholesterol has no effect on the thermodynamics (formal redox potentials) of all-trans MK-7, but the kinetics are affected. Addition of an inert electrolyte (sodium perchlorate; change of ionic strength) to the aqueous phase shifts the redox potentials of all-trans MK-7 only slightly. The formal redox potentials of all-trans MK-4 were determined in TMCL and nCL monolayers and found to be higher in nCL monolayers than in TMCL monolayers. The apparent electron transfer rate constants, transfer coefficients and activation energies of all-trans MK-4 in cardiolipins have been also determined. Most surprisingly, the apparent electron transfer rate constants of all-trans MK-4 exhibit an opposite pH dependence for TMCL and nCL films: the rate constants increase in TMCL films with increasing pH, but in nCL films they increase with decreasing pH. This study is a contribution to understand environmental effects on the redox properties of membrane bond redox systems. Graphical abstract

Calculation of Electron Transfer Rate Constants from Spectra in Re(I) Chromophore−Quencher Complexes

1996 ◽  
Vol 118 (40) ◽  
pp. 9782-9783 ◽  
Author(s):  
Juan Pablo Claude ◽  
Darryl S. Williams ◽  
Thomas J. Meyer
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Transfer Rate ◽  
Electron Transfer Rate
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