Solvent Polarity Effects on Thermodynamics and Kinetics of Intramolecular Electron Transfer Reactions
We present time-resolved fluorescence measurements on an intramolecular electron transfer compound in solvents of different polarity as a function of temperature. In a few solvents the free energy change of the electron transfer and its dependence on temperature and the dielectric constant of the solvent can be determined experimentally. Electron transfer rates are analyzed in terms of activation energies and preexponential factors. Both are found to depend on the polarity of the solvent. The latter is interpreted as evidence for significant entropies of activation.
KeywordsPreexponential Factor Free Energy Change Fluorescence Decay Electron Transfer Rate Butyl Acetate
Unable to display preview. Download preview PDF.
- [1a]R. A. Marcus, J. Chem. Phys. 24, 988 (1956)Google Scholar
- [2a]N. S. Hush, Elektrochem. 61, 734 (1957)Google Scholar
- R. A. Marcus and N. Sutin, Biochim. Biophys. Acta 811, 265 (1985); and references therein.Google Scholar
- H. Heitele, S. Weeren, F. Pöllinger, and M. E. Michel-Beyerle, J. Phys. Chem., in press.Google Scholar
- H. Heitele, P. Finckh, and M. E. Michel-Beyerle, Angew. Chem. 101, in press.Google Scholar
- [17a]R. C. Weast, Handbook of Chemistry and Physics, CRC Press, Cleveland, 1971.Google Scholar
- [17b]J. A. Riddick and W. B. Bunger, Organic Solvents, Wiley-Interscience, New York, 1970.Google Scholar
- [18a]V. O. Levich, Adv. Electrochem. Electrochem. Eng. 4, 249 (1966).Google Scholar
- This estimate ignores specific solvent-solute interactions. Recently, the existence of a simple relation between ΔGCS and e has been questioned .Google Scholar
- [24b]N. Sutin in Supramolecular Photochemistry, ed. V. Balzani, NATO ASI Series C Vol. 214, D. Reidel, Dordrecht, 1987, p. 73.Google Scholar
- [26c]S. Tazuke, N. Kitamura, and H.-B. Kim in Supramolecular Photochemistry, ed. V. Balzani, NATO ASI Series C Vol. 214, D. Reidel, Dordrecht, 1987, p. 87.Google Scholar