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部化学合成项目资助，支持彼得·T·Wolczanski的康奈尔大学探索设计和合成的第一行过渡金属配合物含有配体，扩大了金属的化学，主要是通过氧化和还原过程。配位配体的特征在于具有多氧化还原能力的氮（N）-和碳（C）-供体，即它们是“氧化还原非无辜的”（RNI），这是由于从金属给予或获取电子，从而增加金属的反应性。 Wolczanski集团使用许多第一行过渡金属，如铁和铬，制造出比目前贵金属络合物更具反应性、更环保和可持续性的络合物。 教授Wolczanski和他的小组是活跃在当地社区，积极规划和参与多个星期的课后实验化学俱乐部在卡罗琳小学在伊萨卡，纽约。该研究项目的重点是实验研究，旨在：扩大表达氧化还原非无辜的第一行过渡金属络合物的范围，通过螯合和金属-碳键增加第一行过渡金属的场强，制备能够独特的碳-碳键形成过程的新物种，并基于二碳化物产生金属-碳簇。 氧化还原非无辜（RNI）配体“电子缓冲”过渡金属中心，并扩大他们的能力进行固有的成键和键断裂反应的氧化还原事件。该研究项目的重点是N-供体螯合物在第一行过渡金属络合物化学中的应用，重点是稳定金属-氮和-碳多重键，同时使其具有反应性。可操作的、官能度耐受的第一行烯烃复分解催化剂是关键目标。 制备具有强场的氮基和碳基螯合物对于将第一行过渡金属络合物转化为能够具有第二或第三行反应性的那些是必要的。 研究还集中在C-C键的形成，其特征在于具有自由基特征的金属稳定的碳负离子。自由基烃键活化导致了配体设计的特点，氢原子抽象和C-C耦合，这些键的制作过程进行审查方面的范围和潜在的催化。 研究生和本科生研究人员积极参与该项目的实验和理论方面。 学生接受几种表征技术的培训，包括电子顺磁共振和穆斯堡尔谱以及磁力测量和电子结构计算。

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.