Bifunctional Organometallic Catalysis with Phosphines and N-Heterocyclic Carbenes

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In this project funded by the the Chemical Catalysis Program of the Chemistry Division, Professor Douglas B. Grotjahn and Professor Andrew L. Cooksy of San Diego State University are studying ways to develop the best catalysts for reactions that make organic compounds of interest for a variety of applications, such as pharmaceutical compounds. Organic molecules (ligands) are being designed and synthesized that can bind to a metal atom via one site and to a reacting substrate via another site, and a range of these ligand/metal combinations are being tested for catalytic activity. The fundamental, molecular level steps through which these catalysts function are being studied with the aim of utilizing this information to better design the next generation of ligands. Because catalysis accounts for processes that total one third of the global gross domestic product and a majority of the commercial chemical products and chemical processes, the discovery of new or improved catalysts for organic reactions can have a great impact on economic development and growth. During the course of this research project, undergraduate and graduate students are being trained in the field of catalysis, and a high school outreach program on molecular visualization is being carried out.Professors Grotjahn and Cooksy are using some of the design principles of enzymes, specifically substrate hydrogen bonding and proton transfer, with the aim of accelerating organometallic catalysis. Ligands containing proton-donating or hydrogen-bonding groups are being synthesized and combined with a variety of metal precursors to form metal complexes. The reactions being studied center on waste-free addition or isomerization reactions, with several specific goals: (1) building and applying a toolbox of alkene isomerization catalysts; (2) using ligands to enable X-H activation; (3) developing catalysts for addition reactions; (4) developing protic N-heterocyclic carbene compounds, a newer but promising ligand class with carbene nitrogens bearing an N-H moiety that can engage in hydrogen bonding or proton transfer. The project involves significant one-on-one training of students in modern techniques of organic and organometallic chemistry, including NMR spectroscopy, catalysis screening, and computation. The proposed research has the potential to add new mechanistic insight to our broader understanding of bifunctional catalysis.