Preparation and characterization of gold nanoparticles with a ruthenium-terpyridyl complex, and electropolymerization of their pyrrole-modified metal nanocomposites

The reduction of tetrachloroaurate with sodium borohydride in the presence of 2,29: 69,2"-terpyridyloctanethiol gave terpyridine-functionalized gold nanoparticles ( Tpy-Au, core size 2.0 nm). Metal complexation of Tpy-Au with ruthenium-terpyridyl trichloride, Ru( tpy)Cl-3, led to new gold nanoparticles bearing the ruthenium-terpyridine complex ( Ru-Tpy-Au, core size 5.5 nm) which showed a characteristic MLCT ( metal-to-ligand charge transfer) band in the visible region at 483 nm due to the terpyridine-ruthenium complex and a plasmon resonance at similar to510 nm in the UV-vis spectrum. The redox behavior of Ru-Tpy-Au was studied by cyclic voltammetry. Surface modification of metal electrodes was performed by the electropolymerization of pyrrole-functionalized Ru-Tpy-Au nanoparticles ( Pyr-Ru-Tpy-Au) which were obtained from the ligand-exchange reaction of Ru-Tpy-Au with omega-(N-pyrrolyl) decanethiol.