CAS-Climate: Basicity in the Excited State and under Interfacial Confinement: Fundamentals and Applications to Catalysis

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With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry, Jahan Dawlaty of University of Southern California will study proton transfer reactions near the surfaces of electrodes. The transfer of protons between molecules plays a central role in many of the electrochemical reactions that produce high-value chemicals. However, because these proton transfer reactions happen in trillionth of a second and occur in a layer that is one thousand times thinner than a sheet of paper from the electrode surface, studying them is difficult. Dr. Dawlaty and his students will use advanced laser spectroscopies to trigger proton transfer in small molecules near the electrode surface and study the chemical reactions that take place. Their discoveries could help advance CO2 sequestration strategies, as well as impact solar energy conversion and storage technologies. In addition, the project will provide interdisciplinary research opportunities for graduate and undergraduates students and establish a student exchange program with Bowdoin College for bridging the gap between teaching and research. Under this award, the Dawlaty research team will study the energetics and kinetics of excited state acid-base reactions near electrochemical surfaces using a combination of static and time-resolved absorption and emission methods, as well as interface-specific vibrational spectroscopies. The first aim will focus on small molecules that can be triggered by light to take up protons and use them to drive photocatalytic cycles. The project will explore the molecular principles behind photobasicity, or increased pKa upon photoexcitation, and endeavor to establish design rules for excited state basicity in a range of conjugated heterocyclic molecules and beyond. The second aim will create frustrated Lewis acid-base pairs and explore their potential as pockets of high reactivity for activation of small molecules such as carbon dioxide. The project aims to exploit these phenomena to discover new reactivity in photocatalysis and electrochemistry and apply the lessons learned on excited state proton transfer to reactions that are relevant to energy conversion and storage.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.