Lopes-Costa T, Lopez-Cornejo P, Villa I, Perez-Tejeda P, Prado-Gotor R, Sanchez F
Departamento de Química Física, Facultad de Química, Universidad de Sevilla, c/ Profesor García Gonzalez s/n, 41012 Sevilla, Spain.
J Phys Chem A. 2006 Mar 30;110(12):4196-201. doi: 10.1021/jp055189l.
The title reaction was studied in different reaction media: aqueous salt solutions (NaNO3) and water-cosolvent (methanol) mixtures. The observed rate constants, k(obs), show normal behavior in the solutions containing the electrolyte, that is, a negative salt effect. However, the solvent effect is abnormal, because a decrease of the rate constant is observed when the dielectric constant of the reaction medium decreases. These effects (the normal and the abnormal) can be explained using the Marcus-Hush treatment for electron transfer reactions. To apply this treatment, the true, unimolecular, electron-transfer rate constants, k(et), have been obtained from k(obs) after calculation of the rate constants corresponding to the formation of the encounter complex from the separate reactants, k(D), and the dissociation of this complex, k(-D). This calculation has been carried out using an exponential mean spherical approach (EMSA).
盐水溶液（NaNO₃）和水 - 共溶剂（甲醇）混合物。观察到的速率常数k(obs)在含有电解质的溶液中表现出正常行为，即负盐效应。然而，溶剂效应是反常的，因为当反应介质的介电常数降低时，观察到速率常数减小。这些效应（正常和反常）可以使用马库斯 - 胡什电子转移反应处理方法来解释。为了应用这种处理方法，在计算了由单独反应物形成遭遇络合物的速率常数k(D)以及该络合物的解离速率常数k(-D)之后，从k(obs)中获得了真实的单分子电子转移速率常数k(et)。这种计算是使用指数平均球近似法（EMSA）进行的。
