CAS: Forming Transition Metal Hydride Complexes via Excited-State Proton-Coupled Electron Transfer

在这项由化学系化学结构、动力学和机理B计划资助的项目中，北卡罗来纳大学化学系的Jillian Dempsey教授正在研究将光捕获和质子/电子反应直接整合到配位络合物中的途径。这项研究的目的是为过渡金属氢化物的形成建立新的光子驱动途径。过渡金属氢化物络合物是许多催化过程中的关键中间体，这些过程驱动燃料和商品化学品的形成，因此开发利用太阳光子促进其形成的方法将有助于提高能源密集型催化反应的可持续性。拟议的研究活动将通过为学生提供合成、电化学、光谱学和有效的科学交流方面的培训，帮助培养一支具有全球竞争力的STEM劳动力队伍。补充性活动将采取多方面的方法，以增加科学多样性和加强对科学家的培训。在北卡罗来纳大学科学博览会和当地学校部署的互动桌面活动将向K-12学生介绍可再生能源科学。邓普西教授共同领导了化学女性导师网络，该网络为对学术生涯感兴趣的研究生和博士后女性与校外教师导师牵线搭桥，并提供支持成功的导师关系所需的资源。能够在激发态进行质子耦合电子转移的配位化合物的发展有望揭示金属氢化物配合物的新的光子驱动途径。然而，关于如何在配位络合物中直接结合光捕获和质子电子反应性，特别是制备过渡金属氢化物络合物，从根本上说知之甚少。这项工作将进行系统的研究，以解决这一知识差距，并随后应用加强的理解，以建立前所未有的激发态的配位络合物的反应性。具体地说，本研究将1)加深对支持质子耦合电子转移反应的激发态电子结构的理解，2)证明配位化合物在其电子激发态可以进行质子耦合电子转移反应，形成金属氢化物络合物。最终，证明金属氢化物络合物可以通过激发态质子耦合电子转移形成，这将为光驱动燃料和化学品生产建立一个新的范例。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Jillian Dempsey of the Department of Chemistry at University of North Carolina (UNC) is studying pathways by which light capture and proton/electron reactivity can be directly integrated in coordination complexes. The goal of this research is to establish new photon-driven pathways for the formation of transition metal hydride complexes. Transition metal hydride complexes are key intermediates in many catalytic processes that drive the formation of fuels and commodity chemicals and thus developing approaches to promote their formation with solar photons will help improve sustainability in energy intensive catalytic reactions. The proposed research activities will help develop a globally competitive STEM workforce by providing students with training in synthesis, electrochemistry, spectroscopy, and effective science communication. Complementary activities will take a multi-faceted approach to increase diversity in science and enhance training of scientists. Interactive table-top activities deployed at the UNC Science Expo and local schools will introduce K–12 students to the science of renewable energy. Professor Dempsey co-leads the Chemistry Women Mentorship Network, which matches graduate student and postdoc women interested in academic careers with extramural faculty mentors and provides resources needed to support successful mentoring relationships. The development of coordination complexes capable of undergoing proton-coupled electron transfer in their excited states promises to reveal new photon-driven pathways to metal hydride complexes. However, little is fundamentally known about how to directly integrate light capture and proton electron reactivity in coordination complexes, especially to yield transition metal hydride complexes. This work will carry out systematic studies to address this gap in knowledge and subsequently to apply an enhanced understanding to establish unprecedented excited-state reactivity of coordination complexes. Specifically, this research will 1) Provide a deeper understanding of excited-state electronic structures that support proton-coupled electron transfer reactions and 2) Demonstrate that coordination complexes can undergo a proton-coupled electron transfer reaction in their electronic excited state to form a metal hydride complex. Ultimately, demonstration that metal hydride complexes can be formed via excited-state proton-coupled electron transfer will establish a new paradigm for light-driven fuel and chemical production.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.