CAREER: Quantifying Nitrogen-Oxide (NO) Activation and Coordination Modes through Synthesis, Spectroscopy and Computations

在这个由化学系化学结构、动力学机制B项目资助的CAREER项目中，Sabine Chantal E.位于波莫纳的加州州立理工大学化学系的Stieber正在研究金属中心的小分子反应。利用在大气中发现的小的含氮分子的反应作为农业固氮（例如在豆类中）中涉及的现有生物过程的模拟物或用于减少汽车污染物的健康影响而引起相当大的兴趣。推进金属-氮氧化物相互作用的知识也可以为开发将氮氧化物污染物转化为有用化学品的催化系统提供见解。这项研究特别具有挑战性，因为氮氧化物物种通常不稳定且寿命短，因此需要在国家同步加速器设施中开发新的表征工具。 这些新工具与计算工作以及空气和水分敏感的无机复合物的合成相结合。该项目旨在使本科研究人员能够进行有影响力的研究，并获得一系列技术的经验。该研究通过学生主导的计算化学和晶体学研究模块与教育相结合。 目前表征金属与含氮氧化物物种相互作用的方法不足以提供键合、氧化态和功能化的完整化学表征，所有这些都是开发氮功能化合成系统所必需的。研究含氮氧化物物种的一个关键挑战是分离不稳定的物种并对其进行表征。 为了克服这些稳定性问题，Stieber教授使用光谱技术，为与氮氧化物物种的不同配位数，模式和氧化态结合的金属建立光谱指纹。本项目研究X射线发射光谱（XES）作为一种分析技术，用于表征配位络合物中的配位模式和氧化还原活性。目前的项目利用合成，同步加速器和计算方法来研究更复杂和更具挑战性的系统。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In this CAREER project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Sabine Chantal E. Stieber of the Department of Chemistry at the California State Polytechnic University, Pomona (Cal Poly Pomona) is studying small molecule reactions at metal centers. Reactions utilizing small, nitrogen containing molecules found in the atmosphere are of considerable interest as mimics for existing biological processes involved in agricultural nitrogen fixation (such as in legumes) or for reducing the health effects of automobile pollutants. Advancing the knowledge of metal-nitrogen oxide interactions may also offer insights towards the development of catalytic systems for converting nitrogen oxide pollutants into useful chemicals. This research is especially challenging as the nitrogen oxide species are often unstable and short-lived, and thus require the development of new characterizational tools at a national synchrotron facility. These new tools are coupled with computational efforts and the synthesis of air-and moisture-sensitive inorganic complexes. The project is designed to enable undergraduate researchers to conduct impactful research and gain experience with a range of techniques. The research is integrated with education through student-led research modules in computational chemistry and crystallography. The efforts broaden research opportunities for all students and enable the recruitment of a diverse STEM workforce.Current methods to characterize metal interactions with nitrogen oxide-containing species are insufficient to provide complete chemical characterization of bonding, oxidation states, and functionalization, all of which are necessary for developing synthetic systems for nitrogen functionalization. A key challenge of studying nitrogen oxide-containing species is isolating the unstable species and characterizing them. To overcome these stability issues, Professor Stieber uses spectroscopic techniques that stablish spectral fingerprints for metals bound to different coordination numbers, modes, and oxidation states of nitrogen oxide species. This project examines X-ray emission spectroscopy (XES) as an analytical technique for characterizing coordination modes and redox activities in coordination complexes. The current project utilizes synthetic, synchrotron and computational methods to study more complex and challenging systems.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.