New Reaction Chemistry with Transition Metal Complexes for Conversion of Oxygenated

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With funding from the Chemical Synthesis Program of the Division of Chemistry, Dr. Theodor Agapie of the California Institute of Technology is synthesizing molecular compounds to study the production of liquid fuels from carbon monoxide (CO) as a starting material. Liquid fuels (such as methanol and ethanol) are particularly desirable as they allow the U.S. economy to maintain its current energy infrastructure. While catalysts for the conversion of CO to fuels containing carbon-carbon bonds are known, their reactions are chemically challenging and poorly understood. Dr. Agapie's catalysts are capable of forming products containing the desirable carbon-carbon bonds using CO as a starting material. He is also using these compounds to systematically study the relationship between their structure and reactivity in order to develop a fundamental understanding of the principles controlling their behavior. Such advances help the US stay at the forefront of the energy economy. The Agapie group is involved in outreach activities with high school students in Pasadena, CA. They support the Caltech Classroom Connection, developing relationships with teachers as Marshall Fundamental High School. The visits by high school students and workshops on careers in science have engage students in STEM careers. Undergraduate students participate in the projects under Caltech programs Amgen and WAVE which have the goal of providing research opportunities to facilitate careers in science by students who are underrepresented in science. In addition to technical training, graduate students develop their mentorship skills by working with undergraduates, contributing to the education of a talented workforce. Dr. Agapie is systematically studying structure-reactivity relations of a family of molybdenum complexes in order to develop a fundamental understanding of the design principles controlling the selectivity of reductive coupling and deoxygenation of CO and CO2. Ligand architectures that display the ability to store electrons and change coordination modes are being prepared. Mechanistic and ligand design hypotheses are tested to determine the effect of the nature of donors, ligand lability, reduction potential, and electrophiles on the outcome of CO cleavage and coupling reactions. The use of mild reagents, which is necessary for practical applications, is targeted. Specific challenges that are being addressed include: 1) Determination of ligand effects on the cleavage of CO, to generate a metal carbide; 2) Determination of structural features controlling the extent of CO homologation (C2 vs C3, etc); 3) Determination of pathways for Cn (n greater than or equal to 2) product generation from observed intermediates using mild conditions (H+, H-, H2); 4) Evaluation of reagents that are relevant to practical applications such as protons as electrophiles, and hydride and H2 as sources of protons and electrons. These studies may provide the fundamental knowledge necessary for the design of inexpensive and practical catalysts for upgrading of carbon feedstocks to higher value chemicals and fuels. This project is being conducted by undergraduate and graduate students and is exposing them to several technical areas, including synthesis, spectroscopy, and mechanistic studies, all of which facilitate the development of a well-trained workforce.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.