Collaborative Research: RUI: Coupled Proton/Electron Transfer Reactions of Excited States

在这个项目中，由化学结构，动力学和机制-B计划资助，杜兰大学化学系的Russell Schmehl教授和维拉诺瓦大学化学系的Jared Paul正在开发新的过渡金属络合物，作为能够将质子和电子转移到其他分子的光吸收剂。所研究的金属络合物作为模型系统是重要的，这可能有助于提高太阳能转换器（太阳能电池）的效率。 该项目对太阳能燃料的设计具有直接意义，例如水氧化为氧气，水还原为氢气和二氧化碳还原为氢化产品。调查人员致力于教育公众有关能源和环境的问题。作为这项工作的一部分，保罗博士正在建立一个维拉诺瓦中心，以了解和交流与能源和环境有关的问题，并开发了一个关于可持续发展的本科课程。杜兰大学有定期的科学咖啡馆，主题与能源有关。两位研究人员都致力于为儿童，特别是中学生带来与能源相关的科学话题。 这项研究将涉及博士学位的长期项目。在杜兰大学的本科和硕士水平的研究以及在这两所大学。在维拉诺瓦大学和杜兰大学之间的合作项目中，化学家计划研究铜（I），钌（II）和锇（II）的一系列过渡金属络合物的激发态之间的光触发质子转移，电子转移和质子耦合电子转移（PCET），具有一个羟基化的联吡啶（或菲咯啉）配体和各种电子和/或质子受体。独立检查这些反应中的每一个的动力学的自由能依赖性的能力提供了研究的动机。由于反应是由脉冲激光激发引发的，因此可以跟踪过程的时间演变，并将真正的PCET与其中电子转移先于质子转移的反应区分开来。初步工作表明，不同的配合物，单一的去质子化的配合物和氧化和去质子化的物种在一系列的钌（II）羟基联吡啶配合物的光谱。纳秒脉冲激光瞬态吸收光谱可用于清楚地区分仅表现出质子或仅表现出电子转移的系统，以及其他表现出电子转移后质子转移的系统，以及那些通过耦合质子和电子转移进行反应的系统。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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 and Mechanisms-B Program, Professors Russell Schmehl of the Department of Chemistry at Tulane University and Jared Paul of the Villanova University Chemistry Department are developing new transition metal complexes that serve as light absorbers capable of transferring both protons and electrons to other molecules. The metal complexes under study are important as model systems which may help improve the efficiency of solar energy converters (solar cells). The project is of direct significance to the design of solar fuels such as water oxidation to oxygen, water reduction to hydrogen and carbon dioxide reduction to hydrogenated products. The investigators are committed to educating the public on issues relating energy and the environment. As a part of this work, Dr. Paul is establishing a Villanova center for understanding and communicating issues relating to energy and the environment and has developed an undergraduate course on sustainability. Tulane has regular science cafes on topics related to energy. Both investigators are committed to bringing energy-related science topics to children, particularly middle school aged students. The research will involve long-term projects at the Ph.D. level at Tulane as well as undergraduate and master's level research at both universities. In a collaborative venture between Villanova University and Tulane University, chemists plan to examine optically-triggered proton transfer, electron transfer, and proton-coupled electron transfer (PCET) between the excited states of a series of transition metal complexes of copper(I), ruthenium(II) and osmium(II) having one hydroxylated bipyridine (or phenanthroline) ligand and a variety of electron and/or proton acceptors. The ability to independently examine the free energy dependence of the kinetics of each of these reactions provides motivation for the research. Since the reactions are initiated by pulsed laser excitation, it is possible to track the temporal evolution of the processes and distinguish true PCET from reactions in which, perhaps, electron transfer precedes proton transfer. Preliminary work has illustrated that the optical spectra differ for the complex, the singly deprotonated complex and the oxidized and deprotonated species in a series of ruthenium(II) hydroxybipyridine complexes. Nanosecond pulsed laser transient absorption spectroscopy can be used to clearly distinguish systems that exhibit solely proton or solely electron transfer from others exhibiting electron transfer followed by proton transfer and those that react by coupled proton and electron transfer.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.