CAREER: Cavity-Enforced Structure and Reactivity of High-Valent Iron Oxo, Nitrosyl, and Superoxo Complexes

在化学系化学合成项目的支持下，布兰登R.罗切斯特大学的巴内特正在研究生物启发的铁络合物的合成，这种铁络合物可以在化学反应中促进强碳氢键的断裂。这一过程对于化学工业是必不可少的，在化学工业中，许多重要的过程都需要打破通常化学原料中的这种键。拟议的工作旨在开发进行此类反应的方法，并对碳氢裂解过程进行精细控制。这些研究将进一步制定战略，使新的铁化合物能够用作催化剂，并使原料有效转化为增值产品。协同作用，拟议的工作将开发基本的技术和非技术技能的早期职业培训生，并促进学生从代表性不足的背景在现代化学研究的参与。此外，该项目非常适合来自多个教育层次和社区的学生的推广和培训。除了将本科生研究纳入本项目之外，PI还将启动一系列夏季研讨会，旨在培养本科生化学研究人员的“软技能”。补充这一努力是一个计划，以接口的内城高中学生与拟议的研究，并将虚拟现实技术纳入研究生水平coursew.The拟议的研究将进行C-H激活的机制调查的空腔封闭的铁（IV）-oxos，这将大大有助于在环境和适度升高的温度下处理这些配合物的能力。重要的是，预期空腔的刚性性质允许C-H活化中的空间选择性，由此区域选择性由键的空间可及性而不是其强度决定。将启动对净C-H官能化的调查，以及能够实现催化周转的有针对性的方法。作为范围的扩展，拟议的工作还将阐明空间限制对铁超氧和亚硝酰络合物的电子和几何结构的影响。靶向高价铁螯合物将使用在三角形金属螯合平台上含有有机大环的配体系统来构建。这些被设计成包围并动力学稳定反应性金属结合片段。所提出的工作旨在利用空腔的能力之间的相互作用，以强制低热力学稳定性的构象，抑制常见的降解途径，并控制底物的方法，以实现区域选择性C-H官能化，具有潜在的广泛的科学影响和应用，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进行评估，被认为值得支持审查标准。

With support from the Chemical Synthesis program of the Division of Chemistry, Brandon R. Barnett of the University of Rochester is investigating the synthesis of biologically-inspired iron complexes that can facilitate the breaking of strong carbon-hydrogen bonds during chemical reactions. This process is essential for the chemical industry where many important processes require the breaking of such bonds in the usual chemical feedstocks. The proposed work aims to develop ways to perform such reactions and exert fine control over the carbon-hydrogen cleavage process. These studies will further develop strategies that enable the new iron compounds to be employed as catalysts and enable the efficient conversion of feedstocks to value-added products. Synergistically, the proposed work will develop essential technical and non-technical skill sets of early career trainees and facilitate the engagement of students from underrepresented backgrounds in modern chemistry research. Additionally, this project is well suited for outreach and training of students from across multiple educational levels and communities. Beyond the incorporation of undergraduate research into this project, the PI will initiate a summer workshop series, with the aim of developing the “soft skills” of undergraduate chemistry researchers. Complementing this effort is a plan to interface inner-city high school students with the proposed research, and to incorporate virtual reality technology into the graduate level curriculum.The proposed research will undertake mechanistic investigations of C-H activation by cavity-enclosed iron(IV)-oxos, which will be greatly aided by the ability to handle these complexes at ambient and moderately elevated temperatures. Importantly, the rigid nature of the cavity is anticipated to allow for steric selectivity in C-H activation, whereby regioselectivity is determined by the steric accessibility of the bond rather than its strength. Investigations into net C-H functionalization will be initiated, as will targeted approaches that can enable catalytic turnover. As an extension of scope, the proposed work will also elucidate the effects of spatial confinement on the electronic and geometric structures of iron superoxo and nitrosyl complexes. The targeted high-valent iron complexe will be built using a ligand system that contains an organic macrocycle atop a trigonal metal-chelating platform. These are designed to surround and kinetically stabilize the reactive metal-bound fragments. The proposed work aims to exploit an interplay between the ability of the cavity to enforce conformations of low thermodynamic stability, to suppress common degradation pathways, and to control substrate approach so as to achieve regioselective C-H functionalization, with potentially broad scientific impact and application, if successful.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.