Determining C-H Activation Reaction Mechanisms of Nonheme Iron Catalysts with Ultrafast Multi-Dimensional Multiple-Mode Vibrational Spectroscopy

化学系化学测量与成像项目将资助莱斯大学郑俊荣教授，通过研究反应中间体的特征，阐明含铁有机分子催化碳氢活化机制的细节。郑小组正在利用宽带多维多模振动光谱方法研究关键中间体的结构。郑教授开发的外展项目允许当地高中生有机会参与这项研究，并且正在为高中生设计与日常现象背后的基本分子事件相关的项目，以激发他们对基础物理科学的兴趣。研究生和本科生在研究和教育计划的各个方面都得到了积极的指导和参与。将制作动画卡通，向孩子们展示基本的化学和物理原理。本项目重点研究非血红素催化剂Fe（S,S- pdp）中间氧化剂的结构测定，解决其C-H活化机理的分歧。这些中间体在液体中具有顺磁性和瞬态性质，难以用传统技术分离。为了应对这一挑战，人们正在开发新的超快振动光谱方法，以超快的时间分辨率来解析这些瞬态物质的原位结构。各种试剂和催化剂的有机合成和理论计算正在进行，以达到对反应的全面理解。这项工作的广泛影响包括对血红素和非血红素分子催化的许多C-H活化反应有更深入的了解，并开发了一种新的方法，可以解决传统技术难以解决的无机和有机化学中的许多分子结构。

With this award, the Chemical Measurement and Imaging Program of the Division of Chemistry is funding Professor Junrong Zheng of Rice University to elucidate details of the C-H activation mechanism catalyzed by Fe-containing organic molecules, by studying signatures of the reaction intermediates. The structures of key intermediates are being investigated by a broadband multiple-dimensional multiple-mode vibrational spectroscopy method being developed for these purposes in the Zheng group. An outreach program developed by Professor Zheng is allowing local high school students the opportunity to participate in this research and that projects associated with fundamental molecular events underneath daily phenomena are being designed for high school students to inspire their interest in fundamental physical sciences. Graduate and undergraduate students are being actively mentored and involved in all aspects of the research and education plan. Animated cartoons will be developed to demonstrate basic chemical and physical principles for kids.This project focuses on the structural determinations of the intermediate oxidants of the nonheme catalyst Fe(S,S-PDP), resolving the disagreement about its C-H activation mechanism. The intermediates can be paramagnetic and transient in liquids and difficult to be resolved by traditional techniques. To meet the challenge, novel ultrafast vibrational spectroscopic methods are being developed to resolve the in situ structures of these transient species with an ultrafast temporal resolution. Organic syntheses of various reagents and catalysts and theoretical calculations are being conducted to reach a comprehensive understanding of the reactions. The broader impacts of this work include bringing a deeper understanding of many C-H activation reactions catalyzed by heme and nonheme molecules, and developing a novel method that can resolve many molecular structures in both inorganic and organic chemistry that are difficult for traditional techniques.