Coupling One Electron Photoprocesses to Multielectron Catalysts: Towards a Photoelectrocatalytic System

We investigate a new approach to artificial photosynthetic systems that couples a one-electron organic photovoltaic material to a two-electron catalyst. This approach allows direct photo-production of fuels without requiring sacrificial reagents. The synthesis and characterization of the first such photoelectrocatalytic (PECat) system is described. A series of perylene diimides with appended polypyridyl ligands are synthesized. One compound is complexed to a ruthenium terpyridine catalyst. Illumination in dimethyl formamide solution results in the formation of the perylene diimide anion and irreversible oxidation of the solvent (or residual impurities). In the solid state, the PECat material is electroactive at both semiconductor and catalyst sites throughout the film. The films electrocatalyze the two-electron oxidation of isopropanol to acetone in the dark. A small PECat effect is observed in the solid films.