CAS: Pincer Ligand Base Metal Chromophores for Selective Free Radical Reactions

CAS：用于选择性自由基反应的钳配体贱金属发色团

• 批准号: 2102292
• 负责人: Jake Soper
• 金额: $ 46.5万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102292&HistoricalAwards=false
• 关键词: CAS; Pincer; Ligand; Base; Metal

In this project, funded by the Chemical Structure, Dynamics & Mechanism B Program of the Chemistry Division, Jake Soper of the School of Chemistry and Biochemistry at the Georgia Institute of Technology is developing new transition metal catalysts capable of using visible light to convert aryl carbon–hydrogen bonds into carbon–(trifluoro)alkyl bonds, which are important components of many agrochemicals and pharmaceuticals. The goals of this research are to design new earth-abundant metal complexes that can replace photocatalysts based on precious metals and to elaborate new ways to selectively target individual carbon–hydrogen bonds for radical activation and functionalization. By replacing rare and toxic metal catalysts and stoichiometric, often halogen-containing, oxidants with naturally abundant alternatives, the project forms the basis for new "green" routes to pharmaceutical and materials that protect human health and the environment. In pursuit of these goals, the project also affords opportunities for high school STEM educator development, as well as outreach activities that increase public engagement and science literacy among groups that are traditionally underrepresented in chemistry.Efforts to elaborate photoredox-active chromophores based on first row transition metals are challenged by short charge-transfer excited-state lifetimes that preclude bimetallic reactivity. Research in this project proposes to circumvent this issue by combining the chromophore and organometallic reaction center in single coordination complex, opening new avenues to impart selectivity in photoredox catalysis cycles that occur via kinetically facile radical steps. Central to this strategy is the capacity of new pincer complexes to support photolytic cobalt bond activation leading to extrusion of carbon based radicals, which are active for alkylation, fluoroalkylation, and arylation of (hetero)arenes. Substrate directing groups are proposed to shepherd these radicals to specific aryl carbon hydrogen bonds, giving atypical regioselectivity in photochemical Minisci-type homolytic aromatic substitution.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.

在该项目中，佐治亚州技术研究所化学和生物化学学院的化学结构，动力学和机制B计划资助，杰克·索普（Jake Soper）正在开发新的过渡金属催化剂，能够使用可见光将芳基碳 - 氢键转化为碳 - （trifluoro）烷基的烷基烷基的含芳基碳 - 含芳基碳的含量，这是许多重要的组成型。这项研究的目标是设计新的地球丰富的金属络合物，可以基于贵金属替代光催化剂，并详细介绍新的方法，以选择性地靶向单个碳 - 氢键以进行自由基激活和功能化。通过取代具有自然丰富替代品的稀有和有毒金属催化剂和化学计量，通常含卤素的氧化剂，该项目构成了新的“绿色”途径的基础，这些途径是保护人类健康和环境的新型“绿色”途径和材料。为了实现这些目标，该项目还为高中STEM教育者开发提供了机会，以及外展活动，这些活动会增加传统上不足以使化学成分不足的群体之间的公共参与和科学文献。富于第一行过渡金属的详细介绍光电毒素活性彩色机器，这是由兴奋的热情传播的挑战，即兴奋不已的挑战。在该项目的提案中，通过在单个协调络合物中结合发色团和有机反应中心来解决这个问题，开辟了新的途径，以在通过动力学上的激进步骤中进行的光毒素催化循环中赋予选择性。该策略的核心是新钳子复合物支持光解钴键的活化的能力，从而导致碳基自由基的扩展，这些自由基在酒精，氟烷基化和（Hetero）领域的芳基化方面具有活性。提出了底物指导组将这些自由基推向特定的芳基碳氢键，从而在光化学Minisci-type同型芳香芳香族抗性中给出了非典型的调节性。这项奖项反映了NSF的法定任务，并通过使用该基金会的智力优点和广泛的影响来评估NSF的法定任务。