Professors Anne-Frances Miller, Susan Odom, and Dong-Sheng Yang have received four new grants from the National Science Foundation (NSF). These highly-competitive awards will fund research projects on electron transfer in flavoproteins (Miller), high potential redox couples (Odom), high concentration electrolytes (Odom), and spectroscopy of transient organometallic complexes (Yang).
Prof. Miller has a strong history of studying enzymatic redox catalysis, including the enzymes superoxide dismutase and nitroreductase. A major portion of Miller’s research involves enzyme engineering, focusing on rational design of flavoenzymes to modify their electronic characteristics. Miller explains, “Just as electrical wires carry power to every room in our houses, cells have dedicated proteins carrying a current of electrons from reactions that generate electrons to vital reactions that require them.” Her project, titled “Mechanisms of Energy Conservation in Bifurcating Electron Transfer Flavoproteins”, addresses a newly-recognized class of 'electron transferring flavoproteins' (Etfs) that act as energy brokers, trading quantity for quality by accepting pairs of modest-energy electrons and concentrating their energy onto just one of the pair to produce one high-energy electron. Crucially, this biochemical 'step-up station' makes it possible for cells to fix nitrogen gas from air to generate their own fertilizer, making food production possible where it otherwise would not be. The project seeks to understand how these Etfs accomplish this complex process. Miller’s project aims to articulate the underlying principles of the process, so that they can be designed into human-made devices and materials, to increase our ability to use solar power and boost the efficiency and versatility with which we use electrical energy in general. Ultimately, Miller hopes that this project will help to elucidate principles underlying the versatility and efficiency of bifurcation, for implementation beyond biochemistry.
Prof. Odom established her independent career with a focus on organic redox couples that could be utilized in electrochemical energy storage applications such as lithium-ion batteries and redox flow batteries. Says Odom, “Developing low cost-energy storage solutions is critical to expanding the implementation of solar and wind power. Without the ability to store energy, there is a mismatch between production and consumption that would lead to unreliability of our electrical grid.” Odom further elaborated that while solar and wind power get a lot of attention in the mainstream media, most people think of batteries for powering their portable electronic devices such as cell phones and laptops, not the large stationary batteries that are crucially needed for the grid. Odom’s two NSF grants both focus on organic materials that could serve either as additives or as the main components of batteries. In the project titled “High Potential Redox Couples: Design Strategies for Survival in Diverse Environments,” Odom will develop and study high-oxidation-potential organic compounds to serve as electro-active components of batteries with non-aqueous electrolytes, and to develop a library of shelf-stable and organic radical cation salts for use as chemical reagents. In addition to developing more efficient compounds for overcharge protections in lithium-ion batteries and new reagents for organic synthesis, the research will elucidate reaction mechanisms of radical cations for a greater understanding of the stability and decomposition pathways of these electron-deficient species. In a second project, in collaboration with Fikile Brushett of MIT, titled “Collaborative Research: Establishing Design Principles for Molecular Engineering of High Concentration Redox Electrolytes,” Odom seeks to design of electrolytes for non-aqueous RFBs with high energy density, better stability, and acceptable fluid flow properties. This project will not only establish the foundational knowledge necessary to design electrolytes for next-generation grid storage batteries but will also provide fundamental insights into other electrochemical technologies necessary for a sustainable energy economy.
Prof. Yang is known for molecular activation and catalysis, laser spectroscopy of chemical intermediates, and laser synthesis of nano-scale particles. Hydrocarbon compounds are ubiquitous in nature and the most abundant, low-cost feedstock for functionalized organic chemicals; yet many of which are too inert to participate in chemical reactions under mild conditions. Metal activation helps to mitigate this problem by stimulating inert hydrocarbons to react with other molecules. His project titled “Photoionization and Photoelectron Spectroscopy of Transient Organometallic Complexes,” will examine the way metal atoms interact with the hydrocarbon compounds and detect reactive chemical species in these reactions using laboratory-made instruments and sophisticated laser spectroscopic techniques. The plan is to examine the electron configuration effects of the lanthanide elements and the reactivity-structural relationships of the linear, branched, and cyclic alkanes and functionalized alkane derivatives. Experimental methods include laser-assisted molecular beam reactions; time-of-flight mass spectrometry; mass-analyzed threshold ionization, zero electron kinetic energy, and infrared-ultraviolet photoionization spectroscopy; and slow electron velocity-map imaging. The spectroscopic measurements are supplemented with quantum chemical computations. This work strives to understand and explain metal-mediated hydrocarbon activation reactions.