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

在这个由化学部化学结构、动力学和机理B项目资助的项目中，Lin X. Chen教授和Felix N. Castellano教授正在开发研究具有双金属协同作用的过渡金属配合物所必需的光谱和化学。这些目标分子转化并积累来自阳光的能量，最终驱动光催化反应以产生燃料。通过这些研究获得的知识可能会对化学科学产生革命性的影响，并将提高我们合理设计用于催化、光电子和能源可持续性的化学材料/设备的能力。该研究要求大学研究生使用先进的激光光谱学进行表征，结合最先进的计算化学进行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，为他们提供发展多学科专业知识的广阔训练场地。为了探索化学科学的前沿，并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。本文通过结构因子的系统变化，研究了铂、钼、钨二聚体发色团等一系列双金属化合物的量子相干性。通过二维电子能谱和新分子结构的设计来研究多电子转换过程的机理细节。该研究旨在了解过渡金属配合物中多个金属中心之间的本征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，在两个金属中心之间诱导瞬态成键或断键过程，从而可以对其催化活性的起源和基本反应动力学进行详细的研究。

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.