Potentiostatic modulation of the direction of light-induced electron transfer in a heterosupermolecule

Described is the covalent assembly of heterosupermolecules from TiO2 nanocrystal (TiO2), 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 TiO2 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 TiO2 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 TiO2 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.