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Investigating the Dioxygen Activation Mechanisms of Biologically Relevant Nonheme Iron Complexes

研究生物相关非血红素铁络合物的分子氧活化机制

基本信息

批准号：
1900562
负责人：
Adam Fiedler
金额：
$ 45.53万
依托单位：
Marquette University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1900562&HistoricalAwards=false
关键词：
Investigating Dioxygen Activation Mechanisms Biologically

项目摘要

Bacteria employ a wide variety of iron-containing enzymes to breakdown natural and human-generated compounds in the environment. Such reactions commonly proceed by cleaving the carbon-carbon bonds of the molecules in a process that requires dioxygen (O2) from the atmosphere. The mechanism by which biological iron sites facilitate these O2-dependent reactions is not fully understood, which hinders the design of man-made molecules capable of using O2 as a cheap and environmentally-friendly oxidant. In this project, Dr. Adam Fiedler is generating a series of model systems, ranging from small complexes to supramolecular assemblies, to obtain molecular-level insights into the O2 reactivity of iron in both biological and man-made contexts. A powerful combination of spectroscopic and computational tools is utilized to characterize unstable and transient species that have been proposed (but rarely observed) in Nature. In this way, the project provides a more complete picture of reactions that are essential for the remediation of polluted soils and groundwaters. The interdisciplinary nature of the project offers a valuable training experience in both experimental and theoretical methods for graduate and undergraduate students. Dr. Adam Fiedler collaborates with local teachers to engage high-school students in activities that combine chemistry with artistic expression. This outreach program exposes students to concepts and instrumentation used in the project, thereby increasing scientific literacy and the chances that students pursue college degrees in science. With funding from the CSDM-B Program of the Chemistry Division, Dr. Adam Fiedler of Marquette University is developing synthetic iron-containing complexes that mimic key features of nonheme iron dioxygenases. Dioxygenases that cleave carbon-carbon bonds are critical for the microbial degradation and assimilation of organic compounds that arise from both natural and human sources. However, the O2 activation mechanisms employed by these enzymes are not fully understood. In particular, there is uncertainty regarding the geometric and electronic factors that govern the reactivity of pivotal intermediates featuring superoxo, peroxo, and/or substrate radical ligands. This project combines coordination chemistry, reaction kinetics, spectroscopic techniques, and computational methods to illuminate the complex relationships between structure and reactivity in bio-inspired iron complexes, including transient intermediates of catalytic significance. In addition, new approaches for incorporating well-defined second- and third-sphere ligand architectures are developed. These efforts provide fundamental knowledge regarding O2 activation processes in a variety of metalloenzymes and aid in the design of new oxidation catalysts. The methods used in this research offer interdisciplinary training for undergraduate and graduate-level scientists. Dr. Adam Fiedler is also engaged in outreach activities directed towards high-school students that stimulate interest in science by emphasizing the visually appealing aspects of inorganic chemistry and crystallography.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.

细菌利用各种含铁的酶来分解环境中的天然和人类产生的化合物。这种反应通常通过在需要来自大气的分子氧（O2）的过程中裂解分子的碳-碳键来进行。生物铁位点促进这些O2依赖性反应的机制尚未完全理解，这阻碍了能够使用O2作为廉价且环境友好的氧化剂的人造分子的设计。在这个项目中，Adam Fiedler博士正在生成一系列模型系统，从小的复合物到超分子组装体，以获得对铁在生物和人造环境中的O2反应性的分子水平的见解。一个强大的光谱和计算工具的组合被用来表征不稳定和瞬态的物种，已提出（但很少观察到）在自然界中。通过这种方式，该项目提供了一个更完整的图片的反应是必不可少的污染土壤和地下水的补救。该项目的跨学科性质为研究生和本科生的实验和理论方法提供了宝贵的培训经验。 Adam Fiedler博士与当地教师合作，让高中生参与联合收割机化学与艺术表达相结合的活动。这个推广计划让学生接触到项目中使用的概念和仪器，从而提高科学素养和学生攻读科学大学学位的机会。在化学部CSDM-B项目的资助下，马奎特大学的亚当·菲德勒博士正在开发模拟非血红素铁双加氧酶关键特征的合成含铁复合物。裂解碳-碳键的双加氧酶对于来自自然和人类来源的有机化合物的微生物降解和同化至关重要。然而，这些酶所采用的O2活化机制尚未完全了解。特别是，有不确定性的几何和电子因素，支配的关键中间体的反应性，具有superoxo，peroxo，和/或基板自由基配体。该项目结合了配位化学，反应动力学，光谱技术和计算方法，以阐明生物启发的铁络合物，包括催化意义的瞬态中间体的结构和反应性之间的复杂关系。此外，开发了用于纳入定义明确的第二和第三球配体架构的新方法。这些努力提供了关于O2在各种金属酶中的活化过程的基础知识，并有助于设计新的氧化催化剂。本研究中使用的方法为本科生和研究生水平的科学家提供了跨学科的培训。 Adam Fiedler博士还参与了针对高中生的外展活动，通过强调无机化学和晶体学的视觉吸引力来激发他们对科学的兴趣。该奖项反映了NSF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。