Electrophilic f-Element and d-Element Catalyst Design for Novel Reactions and Materials

Professor Tobin J. Marks of Northwestern University in Evanston Illinois is studying, seeking to understand, and thereby optimize useful new catalytic processes, and closely combining this effort with educational outreach activities. Such catalytic processes are of great importance to the U.S. economy, producing fertilizers, fuels, plastics, pharmaceuticals, coatings, adsorbents, electronics, solar energy materials, and other chemicals on a huge scale. In the future, catalytic processes must be more resource-efficient, non-toxic, and utilize low-cost, earth-abundant metals in more selective, time-efficient, and economically competitive technologies. Addressing these challenges will require a highly skilled national technical workforce, and U.S. colleges and universities must play a decisive role by broadly educating young scientists to confidently attack global-scale problems, while conducting world class research across broad disciplinary fronts. The project involves a multi-faceted, educationally rich mix of homogeneous catalyst design across the periodic table, including catalyst synthesis, catalytic reaction evaluation, and analysis of catalytic reaction products. This educational progression, combined with a highly interactive and well-equipped research team environment, augmented by industrial, national laboratory, and international collaborations, provides excellent training/mentoring for graduate, undergraduate, and postdoctoral scholars from all parts of our society planning meaningful private sector, national laboratory, and/or academic careers. Professor Tobin J. Marks of Northwestern University in Evanston Illinois is coupling hypothesis-driven exploratory molecular/macromolecular synthesis with homogeneous catalysis, and in-depth mechanistic analysis, supported by diverse spectroscopies, density functional theory/energy-span analysis, X-ray diffraction and new electrostatic potential/machine/artificial intelligence (AI) learning tools, to provide the predictive understanding needed to exploit the unusual features of f-element and related d0 transition metal centers. The objective is to discover and understand unusual, ideally non-classical, and potentially useful catalytic transformations benefiting from electrophilic metal centers with large tunable ionic radii, polar metal-ligand bonding, typically fixed formal oxidation states, high lability with respect to ligand exchange, established metal-ligand bond energy trends, general resistance to sulfur poisoning, and unique spectroscopic markers. The objective is to rationally develop new reactivity patterns and mechanisms different from those of typical transition metal catalysts. Worldwide interest in lanthanide-mediated catalysis in the organic chemistry community is gratifying, as is addressing the national need for rare earth and nuclear heavy element researchers. Included in this effort is creating, evaluating, and understanding unusual new polymeric materials and useful starting materials. Future research will encompass three complementary focus areas: 1) Lanthanide-based catalytic processes that transform carbon-heteroelement bonds via unconventional pathways under solventless conditions such as carbonyl and thiocarbonyl transformations, 2) Lanthanide-centered catalytic processes that transform polymer carbon-heteroelement bonds via unconventional pathways under solventless conditions such as polyamide and polycarbonate deconstruction for plastics recycling. 3) Catalytic olefin polymerizations to selectively introduce useful polar functionality for unusual materials properties and biomedical functions. Each activity will benefit from a large existing catalyst library as well as from other synergistic catalytic projects that may utilize this catalyst library or contribute to it. The same is true of equipment for catalyst synthesis and handling as well as equipment for exploratory homogeneous catalytic reactions under a variety of conditions such as high-speed mixing, gas uptake measurement, autoclaves, carousels, and automated Nuclear Magnetic Resonance (NMR) for screening multiple reactions. 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.