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

职业：激发态质子耦合电子转移反应的机理研究

• 批准号: 1452615
• 负责人: Jillian Dempsey
• 金额: $ 60万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2021-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1452615&HistoricalAwards=false
• 关键词: CAREER; Mechanistic; Investigations; Excited; State

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.

化学结构、动力学和机理B项目是对北卡罗莱纳大学Jillian L. Dempsey教授的研究的支持。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将光吸收和质子/电子转移结合起来，并将有助于确定直接与阳光驱动能量密集型PCET反应的新方法。新的合成和光谱学方法使得质子转移和电子转移反应都可以在光学上监测。在提出的模型系统中，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为光吸收与质子和电子转移耦合的途径提供见解。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涉及电子激发态试剂的PCET反应有一个基本的了解。模型系统将包含生物学相关的底物以及被选择的复合物，以揭示新的机制途径，通过这些途径，惰性小分子可以通过激发态试剂的PCET过程被激活。总的来说，这些研究将为这类很少被探索的反应提供更好的理解。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，并确保后代培养出训练有素的科学家。一是开发新型能源互动演示。莫尔黑德天文馆和科学中心以及当地一所小学正在利用这些活动，向K-12学生（其中许多来自代表性不足的群体）介绍太阳能转换领域，并吸引他们从事STEM职业。第二，基于证据的教学方法正在被纳入一门大型化学课程，以提高学生的学习和记忆。第三，化学女性导师网络（ChemWMN）已经建立，并将帮助支持女性追求学术事业。除了教育方面的影响，这项工作将增加对激发态PCET过程的认识，这类反应很少有系统的实验研究，并揭示新的光诱导途径来激活小分子。通过揭示能量密集的ppet反应可以由处于电子激发态的分子引发的途径，有效地将太阳光子转化为化学能的新方法，最终可能会开发出解决太阳能储能挑战的新方法。