Abstract

The cyclic phosphazene trimers [N 3P 3(OC 6H 5) 5OC 5H 4N·Ti(Cp) 2Cl][PF 6] (3), [N 3P 3(OC 6H 4CH 2CN·Ti(Cp) 2Cl) 6][PF 6] 6 (4), [N 3P 3(OC 6H 4-Bu t) 5(OC 6H 4CH 2CN·Ti(Cp) 2Cl)][PF 6] (5), [N 3P 3(OC 6H 5) 5C 6H 4CH 2CN·Ru(Cp)(PPh 3) 2][PF 6] (6), [N 3P 3(OC 6H 5) 5C 6H 4CH 2CN·Fe(Cp)(dppe)][PF 6] (7) and N 3P 3(OC 6H 5) 5OC 5H 4N·W(CO) 5 (8) were prepared and characterized. As a model, the simple compounds [HOC 5H 5N·Ti(Cp) 2Cl]PF 6 (1) and [HOC 6H 4CH 2CN·Ti(Cp) 2Cl]PF 6 (2) were also prepared and characterized. Pyrolysis of the organometallic cyclic trimers in air yields metallic nanostructured materials, which according to transmission and scanning electron microscopy (TEM/SEM), energy-dispersive X-ray microanalysis (EDX), and IR data, can be formulated as either a metal oxide, metal pyrophosphate or a mixture in some cases, depending on the nature and quantity of the metal, characteristics of the organic spacer and the auxiliary substituent attached to the phosphorus cycle. Atomic force microscopy (AFM) data indicate the formation of small island and striate nanostructures. A plausible formation mechanism which involves the formation of a cyclomatrix is proposed, and the pyrolysis of the organometallic cyclic phosphazene polymer as a new and general method for obtaining metallic nanostructured materials is discussed. © Springer Science+Business Media, LLC 2009.