CuAAC-based assembly and characterization of a ruthenium-copper dyad containing a diimine-dioxime ligand framework

The design of molecular dyads combining a light-harvesting unitwith an electroactive centre is highly demanded in the field of artificial photosynthesis. The versatile Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC) procedure was employed to assemble a rutheniumtris-diimine unit to an unprecedented azide-substituted copper diimine-dioxime moiety. The resulting (RuCuII)-Cu-II dyad 4 was characterized by electrochemistry, H-1 NMR, EPR, UV-visible absorption, steady-state fluorescence and transient absorption spectroscopies. Photoinduced electron transfer from the ruthenium to the copper centre upon light-activation in the presence of a sacrificial electron donor was established thanks to EPR-monitored photolysis experiments, opening interesting perspectives for photocatalytic applications.