NSF Award
2400047
With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Eunsuk Kim of Brown University will study new ways to manipulate sulfur in chemical reactions. Sulfur compounds are among the most common and problematic impurities found in crude oil. Their removal is a crucial step in the refining process, necessary to prevent the generation of environmentally harmful products during petroleum combustion, which consumes considerable energy and resources. Conversely, sulfur is a prevalent element in many FDA-approved drugs, highlighting its value in organic synthesis. The project will focus on developing a new class of catalysts capable of efficiently inserting sulfur into molecules or removing it without damaging the remaining parts. It will also train the next generation of scientists, and foster collaboration across different areas of chemistry. Participants will gain valuable research experience applicable to the energy and pharmaceutical industries. Moreover, the program will promote diversity in STEM fields through mentoring underrepresented minorities and female scientists and creating educational materials to inspire future generations.<br/><br/>This project will develop a novel class of responsive sulfur atom transfer (SAT) catalysts that are oxidatively stable and have self-repairing capabilities during catalysis. Two groups of molybdenum-containing catalysts, supported by tridentate and tetradentate ligands, will be systematically synthesized, and their catalytic activities will be compared. The reaction mechanisms will also be investigated. The first group of catalysts, supported by a tridentate ligand frame, is responsive, activating only when suitable substrates are present. The second group, supported by a tetradentate ligand frame, exists in equilibrium between active and dormant forms. The presence or absence of the substrate can shift this equilibrium, functioning like a buffer system. In both cases, unintentionally oxidized catalysts can be regenerated in situ via oxygen atom transfer (OAT) reactions, owing to the catalysts’ unique dual catalytic capability for both OAT and SAT. The catalysts developed from this project will be air-stable and effective under mild conditions, creating an immediate impact in the field of synthetic chemistry. The findings will also have broad applications in both the petroleum and pharmaceutical industries.<br/><br/>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.
