Electrophilic Attack on Coordinated Ligands Involved in Catalysis by Organometallic Complexes

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Dr. Jack Norton, Department of Chemistry, Columbia University, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program of the Chemistry Division for mechanistic studies into organometallic catalysis that involves electrophilic attack on coordinated ligands. Specific objectives include: (1) developing an effective catalyst for asymmetric C=N hydrogenation by an ionic mechanism; (2) explaining how coordinated tertiary amines (the products of C=N hydrogenation) can exchange with the corresponding free amines more rapidly than they dissociate; (3) developing an effective catalyst for the hydrogenation of aziridines and epoxides to straight-chain amines and alcohols; (4) measuring the barriers to enantiomer interconversion for imines, aldehydes, and ketones that are coordinated to electropositive metals; (5) determining if the binding of additional ligands to "constrained geometry" zirconaaziridines is stronger than to zirconocene systems. In connection with (2), a hypothesis that electron transfer initiates anomalously fast tertiary amine exchanges will be tested. In connection with (3), a hypothesis that the regiochemistry of hydride transfer depends upon whether it happens in one-step or in two (i.e., whether electron transfer and hydrogen atom transfer happen simultaneously or consecutively) will be tested.This project addresses issues that have broad important to inorganic chemistry and to organic synthesis. The project will develop new catalytic methodologies for the preparation of species that are important in, e.g., pharmaceutical chemistry. In addition, it will uncover details of how present catalysts operate. Another important goal of the project is the training of undergraduate, graduate, and postdoctoral students for industrial and academic positions. There is also an international component to the project because of a regular interchange of students between the PI's group and that of Prof. G. Erker (Muenster Germany).