Hydrogen Atom Transfer Reactivity of Unsymmetric Bimetallic Complex

俄亥俄州立大学化学系张士宇教授在化学结构、动力学和机理b项目（CSDM-B）和化学合成项目（SYN）的支持下，正在开发模型配合物，以阐明不等效环境对天然蛋白质中双金属中心反应性的影响。本研究的目标是弥合金属酶和模拟酶功能的合成催化剂之间的差距，并揭示对能源、健康和环境科学至关重要的催化剂的新设计策略。研究活动将与本科生和研究生的培训相结合，通过合成无机，光谱和理论方法的结合来解决跨学科的挑战。涉及K-12学生的外展活动也将是资助项目的一部分。在本项目中，将制备两类新的双金属配合物，以再现自然界中普遍存在的双金属活性位点的不对称特征，即(i)不对称次级配位球，（ii）不对称初级配位球，（iii）不对称金属结合（杂双金属中心）。将开发新的方法来量化双金属分化的程度，并建立一套指标（氢原子转移动力学，金属亲和等），以帮助定义成功的目标，提高我们对感兴趣的金属酶的理解。在Aim 1中，我们将合成在一级配位球和二级配位球上具有不相等特征的diccopper模型配合物，以了解位点分化程度是否与氢原子转移速率相关。在目标2中，仿生杂双金属FeMn配合物将被开发，以了解合成FeMn配合物的形成。将比较同结构的FeMn、FeFe和MnMn双金属配合物对氧活化和氢原子转移的反应性，以了解异双金属活性位点的进化意义。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics & Mechanisms-B Program (CSDM-B) and the Chemical Synthesis (SYN) Program of the Chemistry Division, Shiyu Zhang of the Department of Chemistry at Ohio State University is developing model complexes to elucidate the influence of inequivalent environment on the reactivity of bimetallic centers in natural proteins. The goal of this research is to bridge the gap between metalloenzymes and synthetic catalysts designed to mimic enzymatic functions and unveil new design strategies for catalysts fundamental to energy, health, and environmental science. The research activities will be integrated with the training of undergraduate and graduate students in addressing interdisciplinary challenges with a combination of synthetic inorganic, spectroscopic, and theoretical methods. Outreach activities involving K-12 students will also be part of the funded project. In this project, two classes of new bimetallic complexes will be prepared to reproduce ubiquitous unsymmetric features of bimetallic active sites in nature, e.g., (i) inequivalent secondary coordination sphere, (ii) inequivalent primary coordination sphere, and (iii) unsymmetric metal binding (heterobimetallic center). New methods will be developed to quantify the degree of bimetallic differentiation and establish a set of metrics (hydrogen atom transfer kinetics, metal affinity, etc.) to help define success with the goal of improving our understanding of the metalloenzymes of interest. In Aim 1, dicopper model complexes with inequivalent features at the primary and secondary coordination sphere will be synthesized to understand if the degree of site-differentiation correlates with the rate of hydrogen atom transfer. In Aim 2, biomimetic heterobimetallic FeMn complexes will be developed to understand the formation of synthetic FeMn complexes. The reactivity of isostructural FeMn, FeFe, and MnMn bimetallic complexes toward oxygen activation and hydrogen atom transfer will be compared to understand the evolutionary implications of heterobimetallic active sites.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.