Developing Novel Triazole-Ruthenium Carbene Complexes (TA-Ru) for Challenging Olefin Metathesis Transformations

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With support from the Chemical Catalysis Program in the Division of Chemistry, Professor Xiaodong Shi of the University of Maryland-College Park is developing a new class of catalysts that enable challenging olefin metathesis transformations to occur. Olefin metathesis is an important chemical reaction that results in the formation of new carbon–carbon double bonds. While metathesis transformations are being employed in chemical, materials, and biological research, current catalysts are challenged by more those molecules and reactions that require high temperatures. In contrast, the new catalysts that are being developed by Professor Shi and his team show significantly improved stability at higher temperature. As a consequence, these new catalysts enable the synthesis of novel chemical structures that are not accessible using the current suite of metathesis catalysts. These new molecular catalysts will be applied to a number of problems and will not only advance fundamental chemical research but will also impact other scientific areas and industries that rely on the products that come from metathesis, e.g. biotech and pharmaceutical industries, the chemical and material science communities/industries. In addition to advancing the applicability of metathesis across several areas of science, these studies will support the preparation of the next generation of scientists by providing undergraduate and graduate students important training in chemical synthesis and through the organization of meetings that are student-oriented.Ruthenium-carbene metathesis catalysts are broadly applicable in synthetic chemistry. While ruthenium catalysts generally show good reactivity and functional group tolerance, they decompose over time and/or they suffer from thermal instability. Professor Xiaodong Shi and his research group have discovered that readily available triazole ligands impart stability on Ru-carbene catalysts and consequently provide novel reactivity when applied to olefin metathesis reactions. These new catalysts will be optimized for transformations that have been difficult to carry out using the previously reported catalysts. In efforts to better understand the role of the triazole motif, mechanistic studies will also be pursued. In addition, complementary synthetic studies will be pursued to convert the initial catalytic products to value-added synthetic targets that will be useful for chemical biology and medicinal and materials chemistry.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.