Two pyrazoline- and one pyrrolidine-bridged Ru(II)bipyridine-fullerene dyads have been prepared and studied by ultrafast time-resolved spectroscopy. A silver-assisted synthesis route, in which Ag(I) removes the chlorides from the precursor complex Ru(bpy)2Cl2 facilitates successful coordination of the fullerene-substituted third ligand. Upon light excitation of the ruthenium moiety, the emission was strongly quenched by the fullerene. The main quenching mechanism is an exceptionally fast direct energy transfer (kobs > 1 × 1012 s-1 in the pyrazoline-bridged dyads), resulting in population of the lowest excited triplet state of fullerene. No evidence for electron transfer was found, despite the extraordinarily short donor-acceptor distance that could kinetically favor that process. The observations have implications on the ongoing development of devices built from Ru-polypyridyl complexes and nanostructured carbon, such as C60 or nanotubes.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry