CAS: Cu, Fe, and Ni Pincer Complexes: A Platform for Fundamental Mechanistic Investigations and Reaction Discovery

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Melanie Sanford of the University of Michigan is studying catalysts derived from copper, nickel, and iron complexes. These metals are all earth abundant transition metals in contrast to metals such as palladium, rhodium and iridium that are often employed in traditional organometallic chemistry. This project aims to help build the scientific foundation needed to deploy inexpensive, earth abundant catalysts in C-H activation and elaboration chemistries, staple transformations of the chemical and pharmaceutical industries, ultimately enabling the replacement of costly and rare precious metals that currently dominate these industries. It will also provide interdisciplinary training to chemistry PhD students for careers in the STEM (science, technology, engineering and mathematics) workforce. Finally, it will support outreach efforts to engage Michigan middle and high-school students in the scientific process, specifically in hands-on electrochemistry activities (building voltaic piles), thereby encouraging them to become engaged in the future STEM workforce. Under this award, Professor Melanie Sanford and her team at the University of Michigan are studying Cu, Ni, and Fe pincer complexes as a platform for fundamental mechanistic investigations and reaction discovery. The proposed work will interrogate intermediates, pathways, and mechanisms in copper, nickel, and iron-catalyzed directed C–H bond functionalization reactions proceeding via LNC pincer-type intermediates. With all three metals, the mechanisms of cyclometalation and oxidative functionalization will be explored as a function of bidentate directing group, supporting ligands, and oxidant. Experimental approaches will focus on the isolation and/or detection of key intermediates, leveraging 19F NMR spectroscopy as a versatile tool for in situ monitoring of both diamagnetic and paramagnetic species. A key goal of this work is to achieve a deeper understanding of first-row transition-metal catalyzed C–H functionalization reactions, ultimately to inform the development of new catalytic transformations as well as broader applications of LNC pincer complexes in catalysis. 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.