CAS: Cu, Fe, and Ni Pincer Complexes: A Platform for Fundamental Mechanistic Investigations and Reaction Discovery

在化学系化学催化项目的支持下，密歇根大学的梅勒妮·桑福德教授正在研究铜、镍和铁的络合物衍生的催化剂。这些金属都是富含稀土的过渡金属，与传统的有机金属化学中经常使用的金属如钯、铑和铱形成鲜明对比。该项目旨在帮助建立在C-H活化和精制化学中部署廉价、富含稀土的催化剂所需的科学基础，这些催化剂是化学和制药行业的主要转型，最终能够取代目前主导这些行业的昂贵和稀有贵金属。它还将为化学博士生在STEM(科学、技术、工程和数学)劳动力中的职业提供跨学科培训。最后，它将支持扩大努力，让密歇根州的初中生和高中生参与到科学过程中，特别是在动手的电化学活动中(建造伏特堆)，从而鼓励他们参与未来的STEM工作。在这个奖项下，密歇根大学的梅勒妮·桑福德教授和她的团队正在研究铜、镍和铁的钳形络合物，作为基础机理研究和反应发现的平台。这项拟议的工作将询问通过LNC钳型中间体进行的铜、镍和铁催化的定向C-H键官能化反应中的中间体、途径和机制。对于这三种金属，环金属化和氧化官能化的机理将作为双齿导向基团、支持配体和氧化剂的函数来探索。实验方法将侧重于分离和/或检测关键中间体，利用19F核磁共振光谱作为一种多功能工具，对抗磁性和顺磁性物种进行现场监测。这项工作的一个关键目标是加深对第一排过渡金属催化的C-H功能化反应的理解，最终为新催化转化的开发以及LNC钳形络合物在催化剂中的更广泛应用提供信息。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Melanie Sanford of the University of Michigan is studying catalysts derived from copper, nickel, and iron complexes. These metals are all earth abundant transition metals in contrast to metals such as palladium, rhodium and iridium that are often employed in traditional organometallic chemistry. This project aims to help build the scientific foundation needed to deploy inexpensive, earth abundant catalysts in C-H activation and elaboration chemistries, staple transformations of the chemical and pharmaceutical industries, ultimately enabling the replacement of costly and rare precious metals that currently dominate these industries. It will also provide interdisciplinary training to chemistry PhD students for careers in the STEM (science, technology, engineering and mathematics) workforce. Finally, it will support outreach efforts to engage Michigan middle and high-school students in the scientific process, specifically in hands-on electrochemistry activities (building voltaic piles), thereby encouraging them to become engaged in the future STEM workforce.Under this award, Professor Melanie Sanford and her team at the University of Michigan are studying Cu, Ni, and Fe pincer complexes as a platform for fundamental mechanistic investigations and reaction discovery. The proposed work will interrogate intermediates, pathways, and mechanisms in copper, nickel, and iron-catalyzed directed C–H bond functionalization reactions proceeding via LNC pincer-type intermediates. With all three metals, the mechanisms of cyclometalation and oxidative functionalization will be explored as a function of bidentate directing group, supporting ligands, and oxidant. Experimental approaches will focus on the isolation and/or detection of key intermediates, leveraging 19F NMR spectroscopy as a versatile tool for in situ monitoring of both diamagnetic and paramagnetic species. A key goal of this work is to achieve a deeper understanding of first-row transition-metal catalyzed C–H functionalization reactions, ultimately to inform the development of new catalytic transformations as well as broader applications of LNC pincer complexes in catalysis.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.