Potentiostatic Modulation of the Direction of Light-Induced Electron Transfer in a Heterosupermolecule

Described is the covalent assembly of heterosupermolecules from TiO 2 nanocrystal (TiO 2 ), ruthenium complex ( R ) and viologen ( V ) components. Also described is their covalent organization to form a heterosupramolecular assembly. Effective function modulation has proved possible via an intrinsic substrate formed by the TiO 2 nanocrystal components. Specifically, under open circuit conditions or upon application of a sufficiently positive potential to the intrinsic substrate, visible light excitation of the ruthenium complex component results in electron transfer to the TiO 2 nanocrystal component (95%). Alternatively, upon application of a sufficiently negative potential to the intrinsic substrate, visible light excitation of the ruthenium complex component results in electron transfer to both the TiO 2 nanocrystal (48%) and the viologen components (52%). Considered are some implications of these findings for the development of practical devices based on heterosupramolecular function that is addressable and modulatable on the nanometer scale.