LUMINESCENCE, SPECTROELECTROCHEMISTRY AND PHOTOELECTROCHEMICAL PROPERTIES OF A TETRARUTHENATED ZINC PORPHYRIN

We report the spectroelectrochemistry, luminescence and photoelectrochemical properties of a polymetallic complex containing four [Ru(bipy)(2)Cl](+) groups attached to zinc-tetra(pyridyl)porphyrin (ZnTPyP). Six successive redox states involving TPyP, ruthenium, zinc and bipyridine (bipy) species have been characterized spectroelectrochemically in the range -1.8 to 1.7 V vs. a standard hydrogen electrode (SHE). The luminescence properties of the complex in solution are centred on the porphyrin moiety. Fluorescence predominates at room temperature in solution, whereas phosphorescence becomes very effective in the solid state or at low temperatures. In films, the peripheral ruthenium groups exhibit antenna effects promoting efficient energy transfer to the porphyrin, and leading to an enhanced photoelectrochemical response.