Moving electrons in electrocatalysts and through metalloproteins

这一无机化学研究计划正在开发新的方法来设计和合理化小分子催化剂和人工生化系统中的质子耦合电子转移(PCET)反应。我们的长期目标是利用这些系统的基本化学原理来设计下一代催化剂，用于挑战生物氧化(例如，生物修复)和能量储存技术(例如，二氧化碳减少)。本课程侧重于影响两个最基本的化学反应的因素：质子转移和电子转移。这种PCET反应对不同系统的功能至关重要，包括化学催化(例如，二氧化碳的2电子还原为CO和H2O)和蛋白质功能(PCET将酪氨酸氧化为酪氨酸自由基)。 在了解化学和生化反应中PCET的基本特征方面取得了长足的进步，但技术的新发展也提出了新的问题。对于生物氧化还原系统，关于蛋白质如何利用微环境来影响电子转移(ET)的速度和效率的想法一直在继续演变。该提案的长期目标1涉及影响芳香族残基酪氨酸和色氨酸的氧化还原性质的局部非共价相互作用(即微环境)。我们的工作将使用蛋白质模型系统来探索这些新问题，这些蛋白质模型系统是为了测试局部相互作用如何改变ET和PCET酪氨酸化学的速率和能量。长期目标2强调小分子中的微环境效应，这些局部相互作用也对催化剂的功能和性能产生深远的影响。例如，质子继电器的概念改变了分子PCET电催化剂领域。然而，这些分子电催化剂和被视为可扩展技术的催化材料之间仍然存在着基本的知识差距。因此，我们在长期目标2中的努力将通过探索酸/碱化学和金属中心附近带电基团的局部影响，特别是对于二氧化碳和O2还原催化剂，来扩展新兴的铁、钴、Re和Ru催化剂的设计概念。这些思想将被用于基于配位络合物节点的多相催化剂支架的设计和研究。 总体而言，拟议的研究将产生一个基本的理解，即局部基团的组成如何影响氨基酸、蛋白质金属中心、分子电催化剂和材料的氧化还原反应。反过来，这些结果将被用于未来催化剂的设计。我的概念交叉研究计划是开发具有现代实验室技能(包括安全)和备受欢迎的口头/书面沟通技能的高级HQP的试验场。其结果是一个研究小组，是一个多元化和世界级化学的目的地。

This inorganic chemistry research program is developing new approaches to design and rationalize proton-coupled electron transfer (PCET) reactivity in small molecule catalysts and in artificial biochemical systems. Our long-term goals are to use the fundamental chemistry from those systems to design the next generation of catalysts for challenging biological oxidations (e.g., bioremediation) and energy storage technology (e.g., carbon dioxide reduction). This program focuses on the factors that influence the two most fundamental chemical reactions: proton transfer and electron transfer. Such PCET reactions are crucial for function in diverse systems, including in chemical catalysis (e.g., the 2 electron reduction of CO2 to CO and H2O) and protein function (the PCET oxidation of tyrosine to tyrosyl radical). Great strides have been made in understanding the essential features of PCET in chemical and biochemical reactions, but new developments in technology have given rise to new questions. For biological redox systems, thinking has continued to evolve about how proteins use microenvironments to affect the rate and efficiency of electron transfer (ET). Long-term Objective 1 of this proposal addresses the local non-covalent interactions (i.e., microenvironment) that affect the redox properties of the aromatic residues tyrosine and tryptophan. Our work will probe these new questions using protein model systems built to test how local interactions modify the rates and energetics of ET and PCET chemistry of tyrosine. Long-term Objective 2 places emphasis on microenvironment effects in small molecules, where those local interactions also exert a profound influence on catalyst function and performance. For example, the concept of “proton relays” transformed the field of molecular PCET electrocatalysts. However, there remains a fundamental knowledge gap between those molecular electrocatalysts and catalytic materials that are viewed as scalable technologies. Consequently, our efforts in long-term Objective 2 will expand on emerging iron, cobalt, rhenium, and ruthenium catalyst design concepts by probing the local effects of acid/base chemistry and charged groups proximal to metal sites, specifically for CO2 and O2 reduction catalysts. Those ideas will be used to design and investigate heterogeneous catalyst scaffolds based on coordination complex nodes. Overall, the proposed research will generate a fundamental understanding of how the composition of local groups affects redox reactions of amino acids, protein metal sites, molecular electrocatalysts, and materials. In turn, those results will be used in the designs of future catalysts. My conceptually cross-cutting research program is a proving ground for the development of superior HQP with modern laboratory skills (including safety) and highly sought oral/written communications skills. The result is a research group that is a destination for diversity and world-class chemistry.