Tuning Teflon-Coated Earth-Abundant Metal Complexes in Oxidative Catalysis

在化学系化学催化项目的支持下，波士顿大学的琳达·多勒教授和罗克斯伯里社区学院的金伯利·安·斯蒂格利茨教授将研究碳氢键向碳氧键和碳碳键的具体转化。 这些氧化反应是现代化学中广泛存在的重要反应。 最便宜和最可持续的氧化剂是大气中的氧气（O2），但氧气也能够使许多催化剂系统氧化失活。几乎所有在这些氧化反应中利用O2的催化剂都含有使这些反应能够发生的过渡金属。这项工作将扩大目前的努力，以制备新的铜催化剂支持富氟的“聚四氟乙烯涂层”的配体系统，提供稳定的分子催化剂。 研究人员将制备新的化合物，其中钳位配体紧紧地抓住金属原子，以控制O2和基底之间的反应性。该项目还将探测除铜以外的其他金属的氧化，特别是锰和钒，并将研究扩展到含铁系统。一个重要的推动力将是开发在水和空气中表现良好的催化剂，使这些碳氢化合物氧化系统更具可持续性和环境友好性。这项工作的更广泛的影响将涉及本科课程的开发，学生培训，以及波士顿大学和罗克斯伯里社区学院之间的富有成效的合作。 罗克斯伯里社区学院为来自服务不足的少数群体的高比例学生提供指导;因此，这种合作努力将致力于增加STEM（科学，技术，工程和数学）领域的多样性，公平性和包容性。 在这些研究中，波士顿大学的琳达·多勒教授和罗克斯伯里社区学院的金伯利·安·斯蒂格利茨教授将研究C-H键的氧化。这项工作建立在研究人员对Cu/O2化学的先前工作的基础上，该工作已经证明了氟化醇盐配体在氧化C-H键时产生高反应性物种的有效性。将研究氧化还原惰性抗衡阳离子（特别是K）的封装的性质和程度对催化活性的影响。也将寻求Li、Na、Rb和Cs的其它抗衡阳离子，以及将经由两个互补路线进入的基于Fe的催化剂系统。A Bordwell平方法将被用来生成一个建议的{Mn（III）OH}试剂原位，将被用来探测其热力学性质。探索范围和优化反应条件与能够催化C-H键氧化的台式稳定钒化合物将是合作团队在罗克斯伯里社区学院教授的动手实验合成和光谱学课程的一部分。这种持续的合作汇集了过渡金属络合物（Doerrer）和有机化合物表征（Stieglitz）方面的专业知识，并将加强对代表性不足的少数民族学生的STEM职业培训，同时让他们在R1大学进行研究。该奖项反映了NSF的法定使命，并被认为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来支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Linda Doerrer of Boston University and Professor Kimberly Ann Stieglitz of Roxbury Community College will study the specific conversion of carbon-hydrogen bonds to carbon-oxygen and carbon-carbon bonds. These oxidation reactions are widespread and critical reactions in modern chemistry. The cheapest and most sustainable oxidant is atmospheric oxygen (O2) but oxygen also is capable of oxidatively inactivating many catalyst systems. Almost all catalysts that utilize O2 in these oxidation reactions contain transition metals that enable these reactions to take place. This work will expand on current efforts to prepare new Cu catalysts supported by fluorine-rich “Teflon-coated” ligand systems that provide stability to the molecular catalysts. The researchers will prepare new compounds in which clamping ligands hold metal atoms tightly to control reactivity between O2 and the substrate. The project will also probe oxidations using other metals besides Cu, particularly with Mn and V, and will extend the research to Fe-containing systems. An important thrust will be the development of catalysts that perform well in water and air to make these hydrocarbon oxidation systems more sustainable and environmentally friendly. The broader impacts of this work will involve undergraduate course development, student training, and a productive collaboration between Boston University and Roxbury Community College. Roxbury Community College delivers instruction to a high percentage of students from underserved minority groups; thus this collaborative effort will be directed at increasing diversity, equity, and inclusion in STEM (science, technology, engineering and mathematics) fields. In these studies, Professors Linda Doerrer of Boston University and Kimberly Ann Stieglitz of Roxbury Community College will study the oxidation of C-H bonds. This work builds on prior work of the researchers on Cu/O2 chemistry that has demonstrated the effectiveness of fluorinated alkoxide ligands to make highly reactive species for oxidizing C-H bonds. The nature and degree of encapsulation of redox inert counter cations, specifically K, on the catalytic activity will be investigated. Other counter cations of Li, Na, Rb, and Cs will also be pursued, as will an Fe-based catalysts system which will be accessed via two complementary routes. A Bordwell square approach will be used to generate a proposed {Mn(III)OH} reagent in situ that will be used to probe its thermodynamic properties. Exploration of the scope and optimization of reaction conditions with a benchtop-stable vanadium compound capable of catalytic C-H bond oxidation will be part of a hands-on experimental synthesis and spectroscopy class taught at Roxbury Community College by the collaborative team. This continued collaboration brings together expertise in transition metal complexes (Doerrer) and in organic compound characterization (Stieglitz), and will enhance the training of underrepresented minority students for STEM careers while exposing them to research at an R1 university.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.