We present a method for the preparation and deposition of metallic microstructures and nanostructures deposited on silicon and silica surfaces by pyrolysis in air at 800 degrees C of the corresponding metallophosphazene (cyclic or polymer). Atomic force microscopy studies reveal that the morphology is dependent on the polymeric or oligomeric nature of the phosphazene precursor, on the preparation method used, and on the silicon substrate surface (crystalline or amorphous) and its prior inductively couple plasma etching treatment. Microscale and nanoscale structures and high-surface-area thin films of gold, palladium, silver, and tin were successfully deposited from their respective newly synthesized precursors. The characteristic morphology of the deposited nanostructures resulted in varied roughness and increased surface area and was observed to be dependent on the precursor and the metal center. In contrast to island formation from noble metal precursors, we also report a coral of SnP(2)O(7) growth on Si and SiO(2) surfaces from the respective Sn polymer precursor, leaving a self-affine fractal structure with a well-defined roughness exponent that appears to be independent (within experimental error) of the average size of the islands. The nature of the precursor will be shown to influence the degree of surface features, and the mechanism of their formation is presented. The method reported here constitutes a new route to the deposition of single-crystal metallic, oxidic, and phosphate nanostructures and thin films on technologically relevant substrates.

Chiral dioxolanones derived from α-hydroxy acids can act as chiral acyl anion equivalents for addition to ethyl crotonate, nitroalkenes and butenolide. Subsequent flash vacuum pyrolysis results in loss of CO and Bu t CHO to give products. The related N-acyl and N-thioacyl-1,3-oxazolidin-5-ones formed from α-amino acids behave in a quite different way with loss of CO 2 upon pyrolysis leading via N-(thio)acylaziridines to oxazolines and thiazolines. The stereochemistry of these transformations, both relative and absolute, is discussed and a mechanism involving an azomethine carboxylate intermediate is proposed.

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