Intraparticle donor-acceptor dyads prepared using conjugated metal-ligand linkages.

Ruthenium nanoparticles were stabilized by the self-assembly of 1-decyne forming ruthenium-vinylidene interfacial bonds and further functionalized by metathesis reactions with 4-ethynyl-N,N-diphenylaniline (EDPA) and 9-vinylanthracene (VAN). Photoluminescence studies of the resulting bifunctionalized Ru(EDPA/VAN) nanoparticles showed that as both ligands were bound onto the nanoparticle surface, effective mixing of the π electrons occurred leading to the appearance of excitation and emission profiles that were completely different from those of ruthenium nanoparticles functionalized with only EDPA or VAN. Furthermore, in photoelectrochemical studies, the EDPA moieties exhibited a pair of well-defined voltammetric peaks in the dark, which were ascribed to the redox reaction involving the formation of cationic radicals; however under UV photoirradiation the voltammetric features diminished markedly. These results strongly suggest that the particle-bound EDPA and VAN moieties behaved analogously to those of conventional molecular dyads based on the same electron-donating and -accepting units, where the intraparticle charge transfer was facilitated by the conjugated metal-ligand interfacial bonds.