Solvent dynamical effects in electron transfer: comparisons of self-exchange kinetics for cobaltocenium-cobaltocene and related redox couples with theoretical predictions

Inter- or intramolecular electron transfer between triruthenium clusters: we’ll cross that bridge when we come to it

“…The rate constants measured range from 10 6 to 10 8 s −1 M −1 and are shown in Table 1. These rate constants are comparable in magnitude to those found by NMR line broadening methods for many other 0/+ and 0/− couples, though the range seen here of more than an order of magnitude of difference between 1 and 3 is remarkable for analogous selfexchange couples [29][30][31][32][33][34]. In a particularly relevant study reported by Meyer, Ru 3 O(OAc) 6 (py) 3 0/+ exhibited k ET = 1.1 × 10 8 s −1 M −1 in CD 2 Cl 2 [30].…”

Low Reorganization Energy for Electron Self-Exchange by a Formally Copper(III,II) Redox Couple

“… a All rate and equilibrium constants determined at −88 °C, except where noted. b Reference . c Extrapolated from −88 °C using λ in eq . d Reference . …”

The Kinetics of Heterogeneous Electron Transfer Reactions in Polar Solvents

“…It would seem that the FB model overestimates the activation parameters for the homogeneous case perhaps due to effects related to the fact that the two reactants are close to one another in the transition state. This conclusion is supported by the observation that the intercept which gives Aks is significantly smaller than independent estimates of this quantity (2.1 kU mol-1 [89]). When the same analysis is applied to the heterogeneous data, very striking results are obtained using the FB model, the data for the electroreduction of cobaltacene lying on the same line as those for the electrooxidation of the same molecule.…”

“…On the basis of the FB model the activation parameters for these reactions should not be the same, whereas the Marcus model predicts that they are the same. In addition, activation enthalpy data are available for the homogeneous ET between cobaltacinium cation and the cobultocene molecule [89]. For these reasons this system is chosen here for more detailed examination.…”