Organometallic derivatives of polyphosphazenes as precursors for metallic nanostructured materials

Abstract

Co-polyphosphazenes containing anchored organometallic fragments are useful precursors for nanostructured metallic materials. Pyrolysis in air at 800 degrees yields metallic nanoparticles of the type, M degrees/M (x) O (y) /M (z) (P (x) O (y) )/P4O7, depending on the metal used; i.e., M degrees when the metal is a noble metal, metal oxide when the metal is Cr, W and Ru, metallic pyrophosphate when M = Mn and Fe. The organic spacer of the polyphosphazene influences strongly the morphology of the pyrolytic product. The mechanism of formation of the nanostructured materials involves carbonization of the organic matter, which produces holes where the nanoparticles are grown. Reaction of the phosphorus polymeric chain with O-2 yield phosphorus oxide units, which act as a P4O7 matrix to stabilize the nanoparticles and/orP(x)O(y)(-n) for the formation of metallic pyrophosphates. The method appears to be a general and versatile new route to metallic nanostructured materials.