SusChEM: Redox Non-Innocence in N- and C-donor Chelate Complexes of 1st Row Transition Elements: Radical Character in Chemistry

该项目由美国国家科学基金会化学系化学合成项目资助，支持康奈尔大学Peter T. Wolczanski教授的研究，以探索含有配体的第一排过渡金属配合物的设计和合成，这些配体主要通过氧化和还原过程扩展金属的化学性质。配位配体的特征是具有多重氧化还原能力的氮(N)-和碳(C)-给体，即它们是“非氧化还原”（RNI），因为它们从金属中给予或获得电子，从而提高了金属的反应性。Wolczanski集团使用了许多第一行过渡金属，如铁和铬，制造出的复合物具有独特的反应性，比目前的贵金属复合物更环保、更可持续。Wolczanski教授和他的团队在当地社区很活跃，积极策划并参加了纽约伊萨卡卡罗琳小学化学俱乐部为期数周的课后实验。本研究项目侧重于实验研究，寻求：扩大表达氧化还原非纯真的第一行过渡金属配合物的范围，通过螯合和金属-碳键增加第一行过渡金属的场强，制备具有独特碳-碳键形成过程的新物种，以及生成基于二碳化物的金属-碳簇。氧化还原非无辜（RNI）配体“电子缓冲”过渡金属中心，并扩大其进行键生成和键断裂反应固有的氧化还原事件的能力。本研究项目主要研究n -供体螯合物在第一行过渡金属配合物化学中的应用，重点是在稳定金属-氮和-碳多键的同时使其具有反应性。操作，功能耐受，第一行烯烃转化催化剂是一个关键的目标。制备具有强场的氮基和碳基螯合物是将第一行过渡金属配合物转化为具有第二或第三行反应性的配合物所必需的。研究还集中在C-C键的形成上，以具有自由基特征的金属稳定碳离子为特征。自由基碳氢键活化导致配体设计特征为氢原子萃取和C-C偶联；这些bond-making过程在范围和催化潜力方面被仔细审查。研究生和本科生的研究人员积极参与项目的实验和理论方面。学生们接受一些表征技术的培训，包括电子顺磁共振和穆斯堡尔光谱，以及磁强计和电子结构计算。

This project, funded by the NSF Chemical Synthesis Program in the Division of Chemistry, supports the research of Professor Peter T. Wolczanski of Cornell University to explore the design and synthesis of first row transition metal complexes containing ligands that expand the chemistry of the metal, primarily through oxidation and reduction processes. The coordinating ligands feature nitrogen (N)- and carbon (C)-donors with multiredox capability, that is they are "redox non-innocent" (RNI) by virtue of giving or taking electrons from the metal, thereby increasing the metal's reactivity. The Wolczanski group employs many first row transition metals such as iron and chromium, making complexes that are uniquely reactive and more environmentally-friendly and sustainable than current precious metal complexes. Professor Wolczanski and his group are active in the local community, actively planning and participating in multi-week after-school experiments for the Chemistry Club at Caroline Elementary School in Ithaca, New York. This research project focuses on experimental studies that seek to: expand the scope of first row transition metal complexes that express redox non-innocence, increase the field strengths about first row transition metals via chelation and metal-carbon bonds, prepare new species capable of unique carbon-carbon bond-forming processes, and generate metal-carbon clusters based on dicarbides. Redox non-innocent (RNI) ligands "electronically buffer" transition metal centers and expand their ability to conduct redox events inherent to bond-making and bond-breaking reactions. This research project focuses on the application of N-donor chelates to the chemistry of first row transition metal complexes, with an emphasis on stabilizing metal-nitrogen and -carbon multiple bonds while rendering them reactive. Operational, functionality tolerant, first row olefin metathesis catalysts are a critical target. The preparation of nitrogen and carbon-based chelates possessing the strong fields are necessary to transform first row transition metal complexes into those capable of second or third row reactivity. Studies also focus on C-C bond-making, featuring metal-stabilized carbanions that possess radical character. Radical hydrocarbon bond activations have led to ligand design features for hydrogen-atom abstraction and C-C couplings; these bond-making processes are scrutinized with regard to scope and the potential for catalysis. Graduate and undergraduate researchers are actively involved in both the experimental and theoretical aspects of the project. The students receive training in several characterizational techniques including Electron Paramagnetic Resonance and Mossbauer spectroscopies as well as magnetometry and electronic structure calculations.