Mixed-valence complexes bridging ligand nature

For a series of similar class II mixed-valence complexes that differ only in the nature of the bridging ligand, MMCT band energy will increase with increasing distance between the metal ions. This dependence has its origin in the magnitude of x as described by Eq. (19) and has been the subject of study (136,137). The relationship between Eop and the barrier to thermal electron transfer [Eq. (1)] was nicely demonstrated by a correlation between electron-transfer rate constants and intervalence-transfer energies (138) and is shown in Fig. 12. 

Other solvents also studied. The complex may be Class III mixed-valence and this band not metal-to-metal charge transfer see text. Ligand is described as dialkylated malononitrile , presumably di-t-butyl. Mossbauer experiment. Estimated theoretically from spectroscopic data. The nature of the metal-metal bridgings not finally established. E.p.r. experiment. 

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