NSF-ANR CHE: Design and Application of Highly Reactive Redox-Active Organophosphorus Catalysts

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Alexander Radosevich of the Massachusetts Institute of Technology is studying inexpensive chemical catalysts composed of Earth-abundant elements, such as iron and phosphorus, that are capable of making and breaking strong chemical bonds. The new catalysts are potentially important because they provide new opportunities for the conversion of common chemical compounds into higher value products.

By composing the catalysts of earth-abundant elements, the methods that are proposed under this project are inherently responsive to the demands of sustainability in chemical synthesis. Specific reactions to be pursued in this research include new schemes to convert C-H bonds in organic molecules into a range of desirable products. Researchers working with Dr.

Radosevich will receive training in a broad set of spectroscopic, physical, and synthetic chemistry techniques; achieving these training objectives will contribute to a vital workforce that underpins the economic competitiveness of US-based chemical industries. In pursuing these studies, Dr. Radosevich’s laboratory will collaborate with Dr.

Sami Lakhdar of the University of Toulouse in France, an expert in photochemical and mechanistic chemistry required to conduct this project, contributing to ongoing US leadership in international scientific engagement. This project is being conducted as part of a joint activity between NSF and the French Agence Nationale de la Recherche (ANR).

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Alexander Radosevich of the Massachusetts Institute of Technology is studying new molecular constructs composed of earth-abundant elements that enable difficult bond cleavage and atom abstraction reactions via proton coupled electron transfer (PCET). PCET reagents commonly suffer from an inverse scaling relationship between acidity and reduction potential (i.e. thermodynamic compensation) that blunts the ability to modify effective homolytic bond dissociation free energy over a wide range.

In this project compounds based on P(V) moieties with modular and mutually-independent proton- and electron-management domains will be studied, and an experimental physical, thermodynamic, and mechanistic foundation for their ability to perform PCET reactions will be established. The expected outcomes will include: 1) an improved fundamental understanding of the interplay between structure and reactivity in multisite PCET reactions, 2) a rigorous and evidence-based rationale for the thermodynamic and kinetic selectivity of observed H-atom abstraction reactions, and 3) new practical catalytic methods for the construction and functionalization of small organic molecules of increasing complexity via homolytic bond activation.

Taken together, the major impact of this collaborative research will be the establishment of new earth-abundant catalysts exemplified by open-shell P(V) compounds as a useful modality in catalytic PCET activation. This project is being conducted in collaboration with Dr. Sami Lakhdar at the Université Paul Sabatier Toulouse and other researchers in France as part of a joint activity between NSF and the French Agence Nationale de la Recherche (ANR).

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.