Collaborative Research: Ultrafast Excited State Electron and Nuclear Coherences in Transition Metal Dimer Complexes and Their Roles in Photochemistry

在化学系化学结构与动力学机制B项目资助的课题中，林新芳教授、Chen和Felix N. Castellano正在开发研究具有双金属协同性的过渡金属络合物所需的光谱学和化学。这些目标分子转换和积累来自太阳光的能量，最终可以驱动光催化反应产生燃料。通过这些研究获得的知识可能对化学科学产生变革性影响，并将提高我们合理设计催化，光电子和能源可持续性化学材料/设备的能力。该研究使大学研究生能够使用先进的激光光谱进行表征，将最先进的计算化学用于量子力学和分子动力学建模，并利用先进的化学实验室设施进行分子合成，为他们提供了一个广阔的培训基地，以发展多学科专业知识。为了探索化学科学的前沿，确保美国在科学知识前沿的全球竞争力，下一代STEM劳动力迫切需要这样的培训。这项工作通过结构因素的系统变化，研究了一系列双金属化合物（如铂，钼和钨二聚体发色团）的量子相干性。通过二维电子光谱和新的分子结构的设计，使多电子转换过程的机制的细节进行调查。该研究旨在了解过渡金属络合物中多个金属中心之间的内在电子耦合及其对光化学反应性的影响。利用超快激光脉冲作为光源，可以在两个金属中心之间诱导瞬时成键或键断裂过程，从而可以详细研究它们的催化活性起源和基本反应动力学。

In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professors Lin X. Chen and Felix N. Castellano are developing the spectroscopy and chemistry necessary for the study of transition metal complexes featuring dimetallic cooperativity. These targeted molecules convert and accumulate energy from sunlight that can ultimately drive photocatalytic reactions for generating fuels. The knowledge obtained through these studies could be transformative for the chemical sciences and will enhance our ability to rationally design chemical materials/devices for catalysis, optoelectronics and energy sustainability. The research engages university graduate students to use advanced laser spectroscopy for characterization, incorporates state-of-the-art computational chemistry for quantum mechanical and molecular dynamics modeling, and utilizes advanced chemistry laboratory facilities for molecular synthesis, providing them with an expansive training ground for the development of multidisciplinary expertise. Such training is urgently needed for the next generation STEM workforce in order to explore the frontiers of chemical science and to ensure US global competitiveness at the frontiers of scientific knowledge.The work studies quantum coherence in a series of di-metallic compounds, such as platinum, molybdenum, and tungsten dimer chromophores through systematic variation of structural factors. Mechanistic details enabling multiple-electron conversion processes are to be investigated through two-dimensional electronic spectroscopy and by the design of new molecular architectures. The research seeks an understanding of intrinsic electronic couplings between multiple metal centers in transition metal complexes and their influence on photochemical reactivity. Using ultrafast laser pulses as light sources, transient bond-making or bond-breaking processes will be induced between the two metal centers, which enable detailed studies on origins of their catalytic activities and fundamental reaction dynamics.