Facile Synthesis of Various Phosphine-Stabilized Monodisperse Palladium Nanoparticles through the Understanding of Coordination Chemistry of the Nanoparticles

We developed facile synthetic procedures to produce monodisperse palladium nanoparticles stabilized with various phosphine ligands by a better understanding of their coordination chemistry. Compared to small sized phosphines such as triphenylphosphine (TPP), trioctylphosphine (TOP) showed weaker coordination ability to palladium nanoparticles. This result was ascertained based on the 31P NMR spectroscopic results of in situ generated molecular palladium complexes. Since TOP acts as a more efficient surfactant in the preparation of high quality monodisperse palladium nanoparticles than smaller sized phosphines, we conducted surfactant exchange reactions of TOP-stabilized palladium nanoparticles in order to produce monodisperse palladium nanoparticles stabilized with various other phosphines. These monodisperse nanoparticles include monodisperse Pd nanoparticles stabilized with chiral ligands and water-dispersable Pd nanoparticles.