Formation of crystalline nanoclusters of Ag, Cu, Os, Pd, Pt, Re, or Ru in a silica xerogel matrix from single-source molecular precursors

Metal complexes containing bifunctional ligands which possess alkoxysilyl functional groups have been prepared for seven metals of the first, second, or third transition metal series. Incorporation of these single-source precursors into silica xerogel matrixes using sol-gel chemistry affords molecularly doped xerogels. Subsequent thermal treatment of these doped xerogels under reducing or oxidizing-then-reducing conditions affords nanoclusters of Ag, Cu, Os, Pd, Pt, Re, or Ru which are highly dispersed throughout the bulk of the xerogel matrix. Characterization of these nanocomposite materials by TEM, EDS, XRD, and electron diffraction indicates that the metal nanoclusters are highly crystalline. A visible spectrum of the silver nanocomposite shows the expected surface plasmon resonance near 415 nm.