The Electron Transfer Process In Mixed Valence Compounds With A Low-Lying Energy Bridge In Different Oxidation States

Mixed-valence compounds with the iso-cyanidometal-ligand bridge in different oxidation states are used as models for the investigation of the electron-transfer process. We synthesized a series of trimetallic isocyanidometal-bridged compounds with [Fe-CN-Ru-NC-Fe](n+) (n=2-4), in which the one-electron oxidation product (N3+) and two-electron oxidation product (N4+) compounds possess an isocyanidometal bridge whose energy is, respectively lower and slightly higher than the terminal metal centers energies. For the N3+ compounds, the bridge state (Fe-II-Ru-III-Fe-II) and mixed-valence states (Fe-III-Ru-II-Fe-II or Fe-II-Ru-II-Fe-III) could be simultaneously observed on the IR timescale. For the N4+ compounds, as the donor becomes stronger the electron transfer bridge excited state (Fe-III-Ru-II-Fe-III) becomes more and more stable, and even becomes ground state due to the strong electronic coupling between Fe and Ru.