CAS: Catalytic Reactions Using Multinuclear Complexes

With the support of the Chemical Catalysis Program in the Division of Chemistry, Professor Christopher Uyeda of Purdue University is studying catalysts that contain multiple metals in their active sites. Many of the chemical compounds that are used in medicine, agriculture, and polymer chemistry have complex structures that require lengthy synthetic processes.

Catalyst development is playing a critical role in improving the efficiency and sustainability of these processes by cutting the number of synthetic transformations required, by allowing more readily abundant starting materials to be used, and by minimizing the production of waste byproducts. Many of the catalysts currently used in the chemical industry contain only one metal in their active site.

In contrast, many enzymes that carry out challenging reactions contain clusters of multiple metals in their active sites. Taking inspiration from biology, Dr. Uyeda’s research group is designing ligands that support the presence of multiple metals in their active site and is using them to carry out a number of organic transformations.

Because a diverse group of high school, undergraduate, graduate, and postdoctoral researchers participate in this project, this work is also helping to train and develop the next generation scientific workforce. In addition to this, outreach activities are planned that will enable students to learn how commercial products are generated from sustainable resources, such as soybeans.

The overarching goal of this project is to investigate multi-metallic active sites as a strategy to improve the activity and selectivity of homogeneous transition metal catalysts. The approach involves designing new classes of ligands that can bind multiple metals simultaneously while also possessing sufficient electronic flexibility to enable two-electron redox processes, such as oxidative addition, reductive elimination, and oxidative coupling.

These catalysts will be investigated for (i) coupling and cycloaddition reactions of alkenes and 1,3-dienes, (ii) carbonylation reactions using well-defined heterometallic carbonyl clusters, and (iii) asymmetric reactions using chiral ligands. The primary intellectual merit of this project lies in its ability to systematically tune the composition of multi-metallic active sites to gain mechanistic insight into metal–metal cooperativity effects.

While doing this, the Used team will also work to develop sustainable reactions by using earth abundant metals, such as nickel, cobalt, and iron. In addition to this, and important from a sustainable chemistry point of view, the reactions chosen for development here, cycloaddition and coupling reactions of feedstock olefins and small molecules, are by design atom-economical and are expected to produce minimal byproducts.

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.