Professor John Verkade, Chemistry Department, Iowa State University is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division for investigations into free radical silicon chemistry and secondary studies of the phosphatrane reactivity. Thermally formed silane free-radicals will be reagents for the formation of aromatic molecules by alkyne cyclotrimerization. A range of alkynes will be investigated to define the range in substituent size and electronic properties that the cyclotrimerization process can tolerate. The possibility of incorporating two different alkynes into the aromatic product and of using various disilanes and other group 14 cogners will be evaluated. A series of disilicon ring systems will be formed by reactions of disilanes with stoichiometric amounts of alkynes and will be used to produce oxygen bridged disilcyclohexandiene polymers. A minor portion of the investigation will target the synthesis of chiral and novel phosphatrane "superbases."
Alkyne trimerization is an extremely useful transformation that converts acetylenes into aromatic molecules. The simplest example is the cyclization of acetylene to benzene. Since complex aromatic molecules are found throughout nature and are encountered in many, e.g., pharmaceuticals, new methods for preparing them are very significant. This study will target a class of silicon compounds that can facilitate the trimerization. A set of cyclic molecules that contain two silicon atoms will also be prepared. These will be used as precursors to form new polymers that will be more robust than the silicone polymers, which they resemble.
