Early Transition Metal Complexes with Polydentate Polyanionic Ligands as Olefin Polymerization Catalysts

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This project supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program will support the continuation of studies of transition metal polymerization catalysts by Professor J. Boncella of the University of Florida. Studies of transition metal complexes of polydentate, polyanionic ligands will be undertaken with the following objectives: 1) continued development of catalysts for olefin metathesis polymerization and depolymerization with emphasis on the mechanism of action of a recently developed tungsten-based catalyst of N,N'-bis(trimethylsilyl)-o-phenylenediamide, 2) possible applications for C-H bond activation reactions that are observed with this tungsten compound, 3) development of catalysts that will perform both metathesis polymerization and Zeigler-Natta type polymerizations at the same metal center, and 4) the synthesis of a new class of polyanionic ligands based upon the pyrrolide ligand, including some that carry more charge than ligating atoms. This new class of ligands is expected to lead to the synthesis of high oxidation state early transition metal complexes that have unusually low coordination numbers and which may have enhanced reactivity. The properties of transition metal catalysts are critically dependent upon the type and number of groups (ligands) that are attached to the active metal center. This project involves the synthesis and study of several new catalysts. Among objectives of this research are 1) the development of new types of polymerization catalysts that are thermally robust and allow for the polymerization of monomers that cannot currently be polymerized because of catalyst instability, and 2) the development of dual function catalysts that can be used to co-polymerize two monomers that undergo polymerization by different mechanisms.