Bipyridyl-Type Light Harvesting Devices

Balzani, V., Juris, A., Venturi, M., Campagna, S. and Serroni, S., Luminescent and redox-active polynuclear transition metal complexes , Chem. Rev. 1996, 96, 759-833. 

3-dpp)Ru (//-2,3-dpp)Ru(bpy)2 2]2 3] (11.7). Compound 11.7 is an excellent example of the fact that metal complexes need to share the same bridging ligand in order to interact, thus the 12 peripheral Ru + centres, which are not connected to one another in such a way as to allow electronic interaction between them, are all oxidised at the same potential in one single 12-electron process. 

In extending these concepts to very large dendritic systems, it is likely that a wider range of metal ions and ligands will become necessary in order to give a smoothly graduated energy-transfer cascade. 

Metal ions such as Rh(lll), Ir(lll), Pd(ll), Pt(ll) and Pt(lV) may be used, although pyridyl-type ligands are less appropriate in these cases since they do not provide the required orbital energy levels. In such cases, combinations of pyridyl and N—C carbanion ligands, such as deprotonated 

One example is the octanuclear iridium(lll) compound 11.14 which uses the C,N-carbanion ligands 11.12 and 11.13. The periphery of the compound comprises fluorinated 2-phenylpyridine (11.12b) iridium units, linked via bridging ligand 11.13 to similar non-fluorinated iridium(lll) 

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