Effect of pressure-induced freezing on the energy of the intervalence transfer electronic absorption band of binuclear mixed-valence complexes

The Marcus continuum model for the solvent reorientation contribution to the energetics of outer-sphere electron transfer has often been used to analyze the energy of the intervalence transfer (IT) electronic absorption band for a binuclear mixed-valence transition-metal complex. E_op, the energy required to transfer an electron optically in a mixed-valence complex, was measured as a function of pressure for two binuclear mixed-valence complexes in different solvents which freeze at 25°C under pressures < 10 kbar. Essentially no shifts of the IT bands were observed, indicating the inadequacy of the dielectric continuum model for such complexes.