CAREER: Mechanistic Investigations of Excited-State Proton-Coupled Electron Transfer Reactions

凭借这一职业奖，化学结构、动力学和机理 B 项目正在支持北卡罗来纳大学 Jillian L. Dempsey 教授的研究。 Dempsey 教授正在研究一系列模型系统中激发态质子耦合电子转移（PCET）反应的机制。这项工作将揭示如何整合光吸收和质子/电子转移，并将有助于确定直接用阳光驱动能量密集型 PCET 反应的新方法。新的合成和光谱方法使得 PCET 反应的研究成为可能，其中质子转移和电子转移反应都可以通过光学方式监测。在所提出的模型系统中，反应中间体的光学检测、动力学建模、热化学计算和H/D动力学同位素效应都将提供对光吸收与质子和电子转移耦合的途径的深入了解。对驱动力、电子转移距离和质子转移距离等参数进行系统研究将有助于对涉及电子激发态试剂的 PCET 反应有基本的了解。该模型系统将纳入生物学相关的底物以及复合物，这些底物和复合物被选择来揭示新的机制途径，通过这些途径，小惰性分子可以通过 PCET 过程与激发态试剂被激活。总的来说，这些研究将加深对这一类鲜为人知的反应的理解。登普西教授还将启动一项三层方法，旨在促进科学多样性并确保下一代训练有素的科学家。一是开发新能源互动演示。这些活动正在莫尔黑德天文馆和科学中心以及当地一所小学开展，旨在向 K-12 学生（其中许多来自弱势群体）介绍太阳能转换领域，并吸引他们从事 STEM 职业。其次，基于证据的教学方法正在被纳入大型化学课程中，以提高学生的学习和保留率。第三，化学女性导师网络（ChemWMN）已经成立，将帮助支持女性追求学术生涯。 除了教育影响之外，这项工作还将增加对激发态 PCET 过程（一类几乎没有系统实验研究的反应）的了解，并揭示新的光诱导途径来激活小分子。通过揭示电子激发态分子引发能量密集型PCET反应的途径，最终可能会开发出有效将太阳光子转化为化学能的新方法，从而解决太阳能存储的挑战。

With this CAREER Award, the Chemical Structure, Dynamic and Mechanism B program is supporting the research of Professor Jillian L. Dempsey at the University of North Carolina. Professor Dempsey is studying mechanisms of excited-state proton-coupled electron transfer (PCET) reactions in a series of model systems. This work will reveal how light absorption and proton/electron transfer can be integrated and will help identify new approaches to drive energy-intensive PCET reactions directly with sunlight. New synthetic and spectroscopic approaches enable the study of PCET reactions in which both the proton transfer and electron transfer reactions can be monitored optically. In the proposed model systems, optical detection of reaction intermediates, kinetics modeling, thermochemical calculations and H/D kinetic isotope effects will all provide insight to the pathways by which light absorption is coupled to proton and electron transfer. Systematic investigations examining parameters such as driving force, electron transfer distance and proton transfer distance will help develop a fundamental understanding of PCET reactions involving reagents in electronically excited states. The model systems will incorporate biologically relevant substrates as well as complexes that were selected to reveal new mechanistic pathways by which small, inert molecules can be activated through PCET processes with excited-state reagents. Collectively, these investigations will provide an improved understanding of this little-explored class of reactions.Professor Dempsey will also initiate a three-tier approach aimed at promoting diversity in science and ensuring future generations of well-trained scientists. First, new energy-based interactive demos will be developed. These activities, which are being utilized at the Morehead Planetarium and Science Center and a local elementary school, are introducing K-12 students-many of whom are from underrepresented groups-to the field of solar energy conversion and attracting them to STEM careers. Second, evidence-based teaching methods are being incorporated to a large chemistry course in order to improve student learning and retention. Third, the Chemistry Women Mentorship Network (ChemWMN) has been established and will help support women pursuing academic careers. In addition to the educational impacts, this work will increase knowledge of excited-state PCET processes, a class of reactions for which there have been few systematic experimental investigations, and reveal new photo-induced pathways to activate small molecules. By revealing pathways by which energy-intensive PCET reactions can be initiated by molecules in their electronic excited states, new approaches to efficiently convert solar photons into chemical energy, addressing solar energy storage challenges may ultimately be developed.