Aimed syntheses of size-selective phosphine-protected Au nanomaterials
John M. Pettibone and Jeffrey W. Hudgens
The current work describes an approach for aimed syntheses of diphosphine-protected Au clusters composed of < 13 atoms, where reduction of solution precursor complexes drives product formation. The current approach is different from the iterative sampling of reactants and reaction conditions that is most commonly used for the development of new materials. The specific role of the protecting phosphine ligand has been previously characterized as a “surfactant” in Au cluster formation, but our work describes the phosphine ligand having a dual role as a protecting and proactive etching agent. Detailed studies identifying reaction pathways for nucleation, growth and formation allow tight control of product formation and increase product yield for syntheses. The implementation of the synthetic approach lead to the development of the smallest chlorinated cluster along with selective, monodisperse Au cluster formation of Au8, Au9 and Au10 species. The use of nanoclusters as building blocks for higher order structures is of current interest for material development utilizing the bottom-up approach and monodisperse syntheses of different “block sizes” is necessary for advancement.