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Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation
Published on: October 10, 2018
Estimation of electronic coupling for intermolecular electron transfer from cross-reaction data
Stephen F Nelsen1, Michael N Weaver, Yun Luo
1Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706-1396.
The Journal of Physical Chemistry. A
|October 13, 2006
Summary
This study expands electron transfer data, revealing intrinsic rate constants accurately predict cross-rate constants for most reactions. Electronic coupling also influences intermolecular electron transfer rates.
Area of Science:
- Electrochemistry
- Chemical Kinetics
- Computational Chemistry
Background:
- Electron transfer reactions are fundamental in chemistry and biology.
- Marcus theory is a key framework for understanding electron transfer rates.
- Accurate prediction of electron transfer rates is crucial for various applications.
Purpose of the Study:
- To expand the dataset of electron transfer cross-reactions.
- To test the predictive power of Marcus cross-rate theory.
- To investigate the factors influencing intermolecular electron transfer rates.
Main Methods:
- Stopped-flow kinetics and cyclic voltammetry were used to study 206 electron transfer reactions.
- Marcus cross-rate theory was applied for analysis.
- Density functional theory calculations (UB3LYP/6-31+G and UB3LYP/6-31G) were used to compute reorganization energies.
Main Results:
- A dataset of 206 reactions involving 72 couples was compiled.
- Intrinsic rate constants accurately predicted cross-rate constants for 93% of reactions (within a factor of 2).
- Electronic coupling (H'ab) effects were detectable and varied significantly.
Conclusions:
- Intrinsic rate constants are highly predictive of electron transfer cross-reactions.
- Marcus reorganization energy and electronic coupling are key determinants of electron transfer rates.
- The study provides a robust dataset and refined understanding of electron transfer kinetics.
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