Controlling the Rates, Distance, and Direction of Electron Transfer in Ultrafast Inorganic Ground States

在该项目中，由化学部的化学结构，动力学和机制B计划资助，加州圣地亚哥大学化学和生物化学系的Clifford Kubiak教授正在开发进行快速电子电子转移（ET）反应的金属络合物的新组装体。 这些反应由红外光谱监测，其具有皮秒（1万亿分之一秒）的时间分辨率，以跟踪这种超快反应。这些研究的目标是对决定ET反应速率、距离和方向的化学因素有一个基本的了解。 这项工作可能最终为设计分子电子设备铺平道路，如开关和存储器，其功能远远快于当前一代的计算机和传感器。 该项目位于合成化学和物理表征之间的交叉点，为研究生和本科生的前沿研究培训提供了丰富的机会。 控制电子转移的速率、距离和方向广泛影响着生命科学、技术和能源部门。该项目代表了基础研究，但如果成功，最终可能在重要领域造福社会，包括治疗DNA损伤引起的遗传疾病;新一代更快，更小，更便宜的集成电路;人工和自然光合作用的进步以及农业食品生产的改进。Kubiak教授让本科生参与研究，并让K-14学生参与。该组织与加州州立大学蒙特利湾分校（CSUMB）建立了一个新的本科生交流项目，让学生在暑假和学校休息期间从事可以部分在CSUMB和部分在UCSD进行的研究项目。 该研究团队还开发了复杂科学思想的可视化，他们的视频也被广泛分享给研究人员，教育工作者和公众。混合价二聚体的三钌乙酸簇显示丰富的光谱证据的超快ET在长距离。 它们已被证明是富有成效的系统，说明不同的桥接部分，电子结构，化学环境和动力学如何影响ET的动力学障碍。克利福德·库比亚克教授和他的团队计划开发一种更完整的物理化学描述，来描述电子如何通过氢键发生转移。 他们将扩展新复合物的合成，以更好地理解电子离域和氢键之间的相互作用。 此外，他们将在皮秒时间尺度上进行分子内ET的第一个二维红外光谱（2D-IR）研究。 他们将使用合成研究来探测桥接配体动力学及其与ET的关系。本研究将试图证明ET坐标的振动控制，以改变其速率和方向。 最后，该团队将设计和合成新的超分子组装体，这些组装体通过半导体金属氧化物纳米颗粒在悬垂的三钌氧化还原中心之间表现出混合价态。该奖项反映了NSF的法定使命，并通过使用基金会的智力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 of the Chemistry Division, Professor Clifford Kubiak of the Department of Chemistry and Biochemistry at the University of California San Diego is developing new assemblies of metal complexes that undergo fast electron electron transfer (ET) reactions. These reactions are monitored by infrared spectroscopy which has picosecond (1 trillionth of a second) time resolution to follow such ultrafast reaction. The goal of these studies is to develop a fundamental understanding of the chemical factors that determine the rate, distance, and direction of ET reactions. This work may ultimately pave the way towards the design of molecular electronic devices such as switches and memory that function far faster than the current generation of computers and sensors. This project lies at the intersection between synthetic chemistry and physical characterization, providing a rich opportunity for the training of graduate and undergraduate students in cutting-edge research. Controlling the rates, distance, and direction of electron transfer broadly impacts the life sciences, technology, and energy sectors. This project represents basic research but, if successful, could ultimately benefit society in important areas including treatments for genetic disorders caused by damage to DNA; a new generation of faster, smaller, and less expensive integrated circuits; advances in artificial and natural photosynthesis and improvements in agricultural food production. Professor Kubiak involves undergraduate students in research and engages K-14 students. The group has established a new undergraduate exchange program with Cal State University Monterey Bay (CSUMB) for students to pursue research projects that can be performed partly at CSUMB and partly at UCSD during summers and school breaks. The research team also develops visualizations of complex scientific ideas and their videos are also being shared broadly with both researchers, educators and the general public. Mixed-valence dimers of triruthenium acetate clusters display rich spectroscopic evidence of ultrafast ET over long distances. They have proven to be fruitful systems in illustrating how different bridging moieties, electronic structures, and chemical environments and dynamics can impact the kinetic barriers of ET. Professor Clifford Kubiak and his group plan to develop a more complete physical chemical description of how electron transfer occurs across hydrogen bonds. They will expand the synthesis of new complexes to better understand the interplay between electron delocalization and hydrogen bonding. Additionally, they will conduct the first two-dimensional infrared spectroscopy (2D-IR) studies of intramolecular ET on the picosecond timescale. They will use synthetic studies to probe bridging ligand dynamics and its relation to ET. This research will attempt to demonstrate vibrational control of the ET coordinate to change its rate and direction. Finally, the team will design and synthesize new supramolecular assemblies that exhibit mixed valency between pendant tri-ruthenium redox centers through semiconducting metal oxide nanoparticles.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.