2016 New Investigator Grant
Neil Tomson, Ph.D. Assistant Professor, Department of Chemistry, University of Pennsylvania
Coordination Chemistry and Catalysis using Molecular-Scale Electric Fields
The sourcing, management and efficient use of energy poses one of the greatest long-term challenges to societal stability. The economic impact alone of damage to the United States caused by rising global temperatures is projected to reach $1 trillion/year by 2050 (Ackerman, F., et al. NRDC, 2008). One of the most promising methods for mitigating the effects of man-made climate change is to develop technology for storing renewable energy in chemical bonds. Ammonia (NH3) is a particularly appealing molecule for this purpose, but current production methods require energy intensive operating conditions, which, if applied to grid-scale energy storage, would lead to significant operational losses. Decades of research have sought low-energy methods for catalytically reducing N2 to NH3, but this investment has been met with only limited success. The inability of synthetic systems to efficiently functionalize the strong bonds within small molecules like N2, O2, and CO2 highlights a fundamental limitation in current design modalities, suggesting that new concepts for how chemists approach catalysis are in need of development. Recent insight from biochemical research suggests that electrostatic fields may play a crucial role in the ability of biological systems to break strong bonds under ambient conditions. The proposed research program seeks to build on these findings by synthesizing a new class of molecular complexes that will use strong, local, electrostatic fields to effect the controlled breakdown of small molecules. The incorporation of these electric fields is expected to facilitate catalytic turnover by redistributing the electron density within molecules in a way that will reduce the required energy input. Long-term efforts focused on N2 reduction to NH3 will be informed by investigations into how related small molecules behave in the presence of local electrostatic fields. Together, the information gained from these studies will advance our fundamental understanding of catalysis, while impacting the knowledge base of multiple disciplines, including biological systems, materials chemistry, and energy storage.