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

有了这一职业奖，化学结构、动态和机制B项目将支持北卡罗来纳大学的Jillian L.Dempsey教授的研究。邓普西教授正在一系列模型系统中研究激发态质子耦合电子转移(PCET)反应的机理。这项工作将揭示光吸收和质子/电子转移是如何结合在一起的，并将有助于确定直接与阳光进行能量密集型PCET反应的新方法。新的合成和光谱方法使研究PCET反应成为可能，在这种反应中，质子转移和电子转移反应都可以进行光学监测。在所提出的模型体系中，对反应中间产物的光学检测、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关于光吸收与质子和电子转移耦合的途径的见解。对驱动力、电子转移距离和质子转移距离等参数的系统研究将有助于对试剂在电子激发态下的PCET反应有一个基本的了解。模型系统将包括与生物相关的底物以及选定的络合物，以揭示新的机制路径，通过这些新的机制路径，小的惰性分子可以通过带有激发态试剂的PCET过程被激活。总而言之，这些研究将提供对这类鲜为人知的反应的更好了解。邓普西教授还将启动一个三层方法，旨在促进科学的多样性，并确保未来几代训练有素的科学家。首先，将开发新的基于能源的互动演示。莫尔黑德天文馆和科学中心和当地一所小学正在利用这些活动，将K-12年级的学生--其中许多来自代表人数较少的群体--介绍到太阳能转换领域，并吸引他们从事STEM职业。第二，基于证据的教学方法正被纳入一门大型化学课程，以提高学生的学习和记忆能力。第三，化学女性导师网络(ChemWMN)已经建立，将帮助支持追求学术事业的女性。除了教育方面的影响，这项工作还将增加对激发态PCET过程的了解，并揭示新的光诱导激活小分子的途径。PCET过程是一类反应，很少有系统的实验研究。通过揭示处于电子激发态的分子可以引发能量密集型PCET反应的途径，最终可能会开发出将太阳光子有效地转化为化学能、解决太阳能储存挑战的新方法。

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.