DINUCLEAR AND POLYNUCLEAR COMPLEXES AS PRECURSORS TO NANOCOMPOSITE MATERIALS - AN OVERVIEW

Molecularly doped silica xerogels can be prepared via sol-gel procedur es by the addition of low-valent di- or polynuclear complexes containi ng bifunctional Iigands to conventional silica sor-gel formulations. T hese bifunctional ligands contain distal (alkoxy) silyl groups, so tha t the dopant complexes can become covalently incorporated into the sil ica xerogel matrix as it is being formed. Subsequent thermal treatment under solely reducing conditions leads to decomposition of the precur sor complex and to the formation of crystalline nanoparticulate materi al which is highly dispersed throughout the silica xerogel matrix. Suc h dopant complexes act as single-source precursors for silica xerogel nanocomposites containing nanoclusters of Ru, PtSn, CCo3 or Co2P. An o verview of the synthesis and characterization of these nanocomposites is described.