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Designer Silver Catalysts for Tunable C=C and C-H Bond Amination

用于可调 C=C 和 C-H 键胺化的设计银催化剂

基本信息

批准号：
1664374
负责人：
Jennifer Schomaker
金额：
$ 45万
依托单位：
University of Wisconsin-Madison
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-06-01 至 2020-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1664374&HistoricalAwards=false
关键词：
Designer Silver Catalysts Tunable C=C

项目摘要

Designer Silver Catalysts for Tunable C-H and C=C Bond AminationOne of the major challenges facing chemists in the 21st century is identifying cheap and sustainable ways to transform substances obtained from petroleum and biorenewable sources into useful building blocks for the synthesis of critically needed pharmaceuticals, agrochemicals, polymers, and fuels. The carbon-hydrogen single bond (C-H) and carbon-carbon double bond (C=C) are two of the most common chemical bonds in organic compounds and represent convenient locations to introduce new functionality into those compounds. However, it is difficult to achieve a desired reaction at only one specific C-H or C=C bond of the many that are present in a single molecule. In this project, Dr. Schomaker is developing new silver catalysts that transform these bonds to important and useful carbon-nitrogen bonds with high yields, less waste, and with the ability to selectively make many different useful products from a single starting compound. Studies to understand the unique features of silver that enable such high, predictable levels of control over this reactivity are key to designing improved and durable catalysts that efficiently transform precious hydrocarbon feedstocks into valuable materials, even using water as reaction solvent. Dr. Schomaker is active in outreach programs related to her research interests in catalysis to educate and engage the general public, especially young women, in fields related to science, technology, engineering and mathematics (STEM). Her activities include developing hands-on experimental modules centered on topics related to silver catalysis for "Expanding Your Horizons", a STEM-centered program for girls in 6-8th grades, as well as entertaining and educational demonstrations on silver chemistry for "Science is Fun" public presentations.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Jennifer Schomaker of the University of Wisconsin is developing low-cost, modular catalysts for the tunable functionalization of C-H bonds to valuable C-N bonds. Such methods are crucial for streamlined syntheses of pharmaceuticals, agrochemicals, chiral ligands and amine building blocks, but represent a long-standing challenge in the field of catalysis. To address this issue, Dr. Schomaker is pursuing a fundamental understanding of the unique features of silver complexes that enable them to achieve catalyst-controlled transformations of C-H bonds to C-N bonds through metal-catalyzed nitrene transfer processes. A combination of variable temperature (VT) NMR, diffusion spectroscopy, mechanistic and computational studies (density functional theory and higher-level ab initio methods such as CASSCF) are being employed to assess how the features of N-donor ligands influence the electronic structure of the metal nitrene, the dynamic/fluxional behavior of reactive intermediates in solution and promotion of non-covalent interactions between substrate/catalyst to influence the site of the C-H functionalization event. Ultimately, this work is establishing universal design principles for the synthesis of catalysts that facilitate non-directed C-H functionalizations capable of overriding innate reactivity preferences that are extendable to other metals and other C-H oxidation reactions, particularly in an asymmetric context. Dr. Schomaker is also active in a number of STEM outreach programs to engage and educate students in her community about the importance of catalysis in solving challenges that currently face our society. She is particularly interested in increasing the representation of women in STEM disciplines to support the broader impacts of this work.

21世纪化学家面临的主要挑战之一是寻找廉价和可持续的方法，将从石油和生物可再生资源中获得的物质转化为合成急需的药物、农用化学品、聚合物和燃料的有用基石。碳-氢单键（C- h）和碳-碳双键（C=C）是有机化合物中最常见的两个化学键，代表了在这些化合物中引入新功能的方便位置。然而，在单个分子中存在许多特定的C- h或C=C键，仅在一个特定的C- h或C=C键上实现所需的反应是困难的。在这个项目中，Schomaker博士正在开发新的银催化剂，将这些键转化为重要而有用的碳氮键，产量高，浪费少，并且能够从单一的起始化合物中选择性地产生许多不同的有用产物。研究银的独特特性，使其对反应性的控制达到如此高的、可预测的水平，这是设计改进的、耐用的催化剂的关键，这些催化剂可以有效地将宝贵的碳氢化合物原料转化为有价值的材料，甚至使用水作为反应溶剂。Schomaker博士积极参与与其催化研究兴趣相关的外展项目，在科学、技术、工程和数学（STEM）相关领域教育和吸引公众，特别是年轻女性。她的活动包括为6-8年级的女孩开发以银催化相关主题为中心的动手实验模块，为“拓展你的视野”，一个以stem为中心的项目，以及为“科学是有趣的”公开演讲提供银化学的娱乐和教育示范。在化学部化学催化项目的资助下，威斯康星大学的Jennifer Schomaker博士正在开发低成本的模块化催化剂，用于将碳氢键可调功能化为有价值的碳氮键。这些方法对于药物、农用化学品、手性配体和胺基的流线型合成至关重要，但在催化领域代表了一个长期的挑战。为了解决这个问题，Schomaker博士正在寻求对银配合物独特特征的基本理解，这些特征使它们能够通过金属催化的亚硝基转移过程实现催化控制的C-H键到C-N键的转化。结合变温核磁共振（VT）、扩散光谱、机制和计算研究（密度泛函理论和更高水平的从头算方法，如CASSCF）正在被用来评估n给体配体的特征如何影响金属亚硝基的电子结构。反应中间体在溶液中的动态/流动行为以及促进底物/催化剂之间的非共价相互作用以影响C-H功能化事件的位置。最终，这项工作是建立催化剂合成的通用设计原则，促进非定向碳氢官能化，能够超越固有的反应性偏好，可扩展到其他金属和其他碳氢氧化反应，特别是在不对称环境下。Schomaker博士还积极参与许多STEM外展计划，以吸引和教育她所在社区的学生了解催化在解决当前社会面临的挑战中的重要性。她特别感兴趣的是增加女性在STEM学科中的代表性，以支持这项工作的更广泛影响。