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计划通过研究反应中间产物的特征，资助莱斯大学的郑俊荣教授通过研究含铁有机分子催化的C-H活化机制的细节。主要中间体的结构正在通过郑组为此目的开发的宽带多维多模振动光谱方法进行研究。郑教授开发了一个推广项目，让当地高中生有机会参与这项研究，并正在为高中生设计与日常现象下的基础分子事件相关的项目，以激发他们对基础物理科学的兴趣。研究生和本科生正在积极指导和参与研究和教育计划的各个方面。将制作动画片，为儿童演示基本的化学和物理原理。本项目重点是非血红素催化剂铁(S，S-PDP)中间氧化剂的结构测定，解决对其C-H活化机理的分歧。这些中间体在液体中可能是顺磁性和瞬变的，很难用传统的技术来分解。为了迎接这一挑战，人们正在开发新的超快振动光谱方法来以超快的时间分辨率来解析这些瞬变物种的原位结构。目前正在进行各种试剂和催化剂的有机合成和理论计算，以全面了解这些反应。这项工作的更广泛的影响包括加深对许多由血红素和非血红素分子催化的C-H活化反应的理解，以及开发一种新的方法来解析传统技术难以解决的许多无机化学和有机化学中的分子结构。

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.