| Abstract
| - A theoretical analysis of the electron-transfer matrix element,Vab, for some cluster modelsintendedto mimic the properties of the[NEt4][Cu2Cl4]mixed-valence compound prepared by Willet et al. isreported.On the basis of ab initio unrestricted Hartree−Fockcalculations, both Vab and the potential energyprofilesversus an idealized electron-transfer reaction coordinate have beencalculated for different scenarios. Ourbest estimate for Vab is found to be 971cm-1 in agreement with experimental relatedwork. The physicalfactors governing the amplitude of the electronic coupling as well asthe shape of the energy profiles havebeen analyzed. It is shown that in order to account for a correcttype II behavior within the Robin−Dayclassification, the polarization effects induced on the cluster by theenvironment have to be included. Thedependence of Vab on the nature of the ligandsbridging the CuI−CuII centers is discussed.Our results for afamily of compounds of formula[Cl2CuIX2CuIICl2]3-(X = Cl-, OH-, SH-) showthat both Vab and the energyprofiles are largely dependent on the nature of X.
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