Bifunctional Catalysts for MHAT Hydrofunctionalization of Alkenes

用于烯烃 MHAT 加氢官能化的双功能催化剂

• 批准号: 2400341
• 负责人: Ryan Shenvi
• 金额: $ 57.5万
• 依托单位: The Scripps Research Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2400341&HistoricalAwards=false
• 关键词: Bifunctional; Catalysts; MHAT; Hydrofunctionalization; Alkenes

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Ryan Shenvi of Scripps Research will study a new type of base metal catalysis. Chemical reactions that produce commercial products and experimental new materials can create a heavy economic and environmental burden. When these reactions are catalyzed by small quantities of precious metals (e.g. platinum, gold, iridium), these burdens can be lessened. However, obtaining and removing these precious metals can create their own environmental, economic and political problems. This research seeks to replace precious metal catalysts with earth abundant metal catalysts such as iron. Through this work, old chemical reactions and existing materials can be made with fewer negative impacts. In addition, these catalysts enable new chemical reactions and novel materials that are unavailable to precious metals. Through these efforts, a diverse body of graduate students will be trained to enter the science and technology workforce. Chemical outreach activities from the Shenvi group to community schools are planned to engage the next generation of science and technical professionals.Alkene cross-coupling traditionally involves precious metal complexes that undergo sequential two- electron, inner-sphere reactions. These pathways involve sequential activations of substrate in which the metal center bonds covalently to intermediates: oxidative addition, coordination, migratory insertion, β- hydride elimination, decomplexation. Each of these steps can restrict the substrate scope, especially the alkene coordination step, whose rate decreases with increased alkene substitution due to steric repulsion. A lesser studied alkene reaction pathway involves metal hydride hydrogen atom transfer (MHAT), a subset of proton-coupled electron transfer (PCET). This outer-sphere elementary step generates a carbon- centered radical directly from an alkene without the need for redox-active auxiliaries or trialkyltin hydrides. In contrast to inner-sphere, coordinative metal-hydride reactions that decelerate with increasing alkene substitution, MHAT reactions can occur at high rates on tetrasubstituted alkenes or amidst steric crowding, even in dilute aqueous buffer among tertiary amines and biomolecules like DNA. The proposed research will study and expand a novel class of MHAT-based alkene functionalization reactions in which a base metal catalyst mediates bond formation at each olefinic carbon without any intermediate metal-carbon bond formation. Problems at the intersection of reactive intermediate chemistry, complex molecule synthesis and ligand design will be addressed through this work. New bioactive materials, chemical reactions and catalyst insights are expected to result from this research into catalysis.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.

在化学催化计划的支持下，Scripps Research的Ryan Shenvi教授将研究一种新型的碱金属催化。产生商业产品和实验新材料的化学反应会造成巨大的经济和环境负担。当这些反应被少量的贵金属（例如铂，金，虹膜）催化时，可以减少这些燃烧。但是，获得和去除这些贵金属可以创造自己的环境，经济和政治问题。这项研究旨在用大量的金属催化剂（例如铁）代替贵金属催化剂。通过这项工作，旧的化学反应和现有材料可以产生更少的负面影响。此外，这些催化剂可实现新的化学反应和新型材料，这些反应是贵金属不可用的。通过这些努力，将对研究生的潜水员团体进行培训，以进入科学和技术劳动力。从申维集团到社区学校的化学外展活动计划参与下一代科学和技术专业人员。传统上，交叉耦合涉及经历顺序的两电子，内部球形反应的贵重金属络合物。这些途径涉及底物的顺序激活，其中金属中心与中间体共价键：氧化添加，协调，迁移插入，β-氢化物消除，解解。这些步骤中的每一个都可以限制底物范围，尤其是烯烃的协调步骤，其速率随着由于空间排斥而增加的烯烃取代而降低。较小的研究烯烃反应途径涉及金属氢化氢原子转移（MHAT），这是质子耦合电子转移（PCET）的子集。这个外部小学的步骤可直接从烯烃中产生以碳为中心的基础，而无需氧化还原活跃的辅助机或试验性甲基氢酯。与内球体相比，坐标金属 - 水溶剂反应随着烯烃的替代而减速，MHAT反应也可以在四碱成立的烯烃或中间的平原拥挤中以高速发生，即使在稀释的氨水缓冲液中，在第三型胺和生物分子中的稀碱性缓冲液也可以像DNA一样。拟议的研究将研究和扩展一类新的基于MHAT的烯烃功能化反应，其中碱金属催化剂介导了每种烯烃碳的键形成，而没有任何中间金属碳键的形成。反应性中间化学，复杂分子合成和配体设计的问题将通过这项工作解决。预计这项对催化的研究产生了新的生物活性材料，化学反应和催化剂见解。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准来评估，被认为是珍贵的支持。