Redox-active metal-polypyridine dendrimers

Redox-Active Metal-Polypyridine Dendrimers as Light-Harvesting Antennae... 

The hexanuclear Ru6 species has four outer and two inner metal centers oxidation active. Both in acetonitrile at room temperature ( 1/2 at + 1.52 V) and in liquid S02 at low temperature ( 1/2 at + 1.46 V), an oxidation process involving the practically simultaneous one-electron oxidation of the four outer Ru(II) centers is evidenced (Fig. 5.9 and Table 5.1). This confirms that the electronic interaction between metal centers that are not directly connected via a bridging ligand is negligible from an electrochemical viewpoint in the metal-polypyridine dendrimers. At more positive potentials, only recordable in liquid S02 at low temperature (Fig. 5.9), a bielectronic process, related to the simultaneous one-electron oxidation of the two inner metal centers at + 2.11 V, is found. This result was at a first sight surprising, since the redox... 

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