Abstract
The physical basis of the solvent contribution to the intrinsic activation entropy, ΔS*int, for outer-sphere electron-transfer reactions in homogeneous solution is examined in terms of the entropic parameters for the constituent electrochemical half-reactions. A relationship for calculating ΔS*int is derived which takes into account specific reactant-solvent interactions for the isolated redox centers by employing electrochemical reaction entropy data. This relation yields rather larger and more structure-sensitive values of ΔS*int, than those deduced on the basis of the usual dielectric continuum treatment. These considerations indicate that the more negative values of ΔS*int typically extracted from experimental kinetic data arise largely from the modification to the specific reactant-solvent interactions within the precursor complex caused by the proximity of the other redox center.
Original language | English |
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Pages (from-to) | 1860-1864 |
Number of pages | 5 |
Journal | Journal of Physical Chemistry |
Volume | 88 |
Issue number | 9 |
Publication status | Published - 1984 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry