With this award, the Chemical Catalysis Program of the Chemistry Division is funding Professor Patrick Holland of Yale University to study new catalysts for the transformation of hydrocarbons to more complex chemicals. Efficient catalytic reactions are a key part of sustainable chemistry, and the most desirable catalytic reactions utilize metals that are both abundant and inexpensive. Inexpensive "base metals," such as cobalt, are more sustainable than precious metals, such as platinum, because of cost, geographic availability, and environmental friendliness. The last decade has seen the discovery of selective base metal catalysts, but their reactivity has less conceptual underpinning. This project endeavors to develop cobalt-containing catalysts that are cheaper than existing catalysts and that give new products that can be applied to fine chemical production. A fundamental understanding of the bond-forming and bond-breaking reactions performed by the catalyst is being developed, which informs a broader range of chemists interested in the underlying chemical principles. The project participants are also involved in the development and implementation of new teaching modules on sustainability for high-school chemistry students in New Haven, Connecticut. These modules are unlocking the students' curiosity about Science, Technology, Engineering, and Mathematics (STEM) fields in the context of the environment and improving the public perception of chemistry.
Professor Holland is studying catalytic systems that perform alkene transformations using high-spin organometallic complexes of cobalt. These inexpensive cobalt catalysts have kinetic selectivities that differ from traditional precious metal catalysts and demonstrate the opportunities that arise from new base metal-catalyzed reactions. The practical developments in catalysis are being complemented by mechanistic studies and DFT computations that elucidate the roles of spin-state crossover during the reactions. Mechanistic and computational studies are providing a fundamental basis for the rational design of high-spin, first-row catalysts. These research strategies are being applied primarily to two specific targets, alkene isomerization and alkene hydrosilylation. Studies on alkene isomerization are focusing on cobalt catalysts for the conversion of terminal alkenes to Z-2-alkenes with high regioselectivity and stereoselectivity. Studies on alkene hydrosilylation are focusing on developing cobalt catalysts for the robust and rapid anti-Markovnikov hydrosilylation of alkenes. The two reactions are also being combined in tandem isomerization-hydrosilylation reactions that convert mixtures of alkenes into a single desired product.
