CAS: First Row Metal Pincer Catalysts: Exploitation of a Long-Lived Nickel(II) Excited State for Self-Sensitized Carbon Dioxide Reduction and Beyond

With the support of the Chemical Catalysis Program in the Division of Chemistry, Professor Elizabeth Papish of the University of Alabama is studying the development of nickel catalysts for the conversion of carbon dioxide to fuel precursors and organic building blocks for pharmaceutical products. Carbon dioxide is readily available from fossil fuel combustion, but it is challenging to use in chemical reactions. New nickel complexes have been discovered with record-setting, long-lived excited states, which serve to capture solar energy and enable new catalytic transformations with carbon dioxide. Current work ongoing in the Papish group includes 1) systematically modifying new nickel and cobalt catalysts to improve their activity for reactions with carbon dioxide, 2) studying the reactivity of these molecules using spectroscopy, crystallography and other methods to understand and visualize how the molecules interact to lead to a lower energy pathway, and 3) testing new types of reactivity to insert carbon dioxide into organic molecules and thereby form valuable products which can lead to fuels, pharmaceutical products, and other high value chemicals. This project is being used to train graduate and undergraduate students at the University of Alabama. There is an urgent need to develop better catalysts to use abundant carbon dioxide sources for commodity chemical synthesis. Specifically, Prof. Papish and her research team are determining how ligand structure-function relationships of nickel metal-organic complexes influence the lifetime of their excited state to improve their reactivity. Mechanistic studies are further being used to elucidate how the lifetime of the nickel catalyst excited state influences reactivity between carbon dioxide and organic substrates. These results of these activities are then being used to guide the design of new organometallic photochemical catalysts for carbon dioxide reduction and organophotoredox chemistry. The results of this work are being publicized by presentations at conferences and are reported in scientific journal articles. Prof. Papish and her group also use catalysis research to provide lessons in science ethics to undergraduate and graduate students. 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.