This project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is in the area of transition metal organometallic chemistry. The focus of the project is compounds in which the organic molecule pentadiene is coupled with the so-called transition metals, such as titanium, vanadium and chromium. Such compounds are similar to the the compounds of cyclopentadiene which are used extensively as industrial catalysts, and the substitution of pentadiene for cyclopentadiene brings about substantial enhancements of thermal stability and chemical reactivity. Potential applications of the pentadienyl compounds include the deposition of metal films and the catalysis of polymerization reactions. The preparation of new open metallocenes, i.e., bis(pentadienyl)metal compounds, will be attempted for manganese and for second and third row transition metals, following up on the preparation of such a compound of zirconium, for which no bis(cyclopentadienyl) compound is known. The structures of the new compounds will be determined, and their reaction chemistry will be explored. The utilization of highly-substituted pentadienyl ligands will be explored, especially ligands with silyl and siloxy substituents. Bimetallic compounds containing "open fulvalene" ligands will be prepared so that metal-metal communciation via the linked pentadienyl ligands may be explored. Potential applications of pentadienyl coupling reactions will be explored, involving such reagents as nitriles, isonitriles, alkynes, imines, and acyl groups. Some of the latter reactions are expected to involve useful ring-forming reactions, leading in some cases to bicyclic organic molecules.
