Development of Stereospecific Controlled/Living Radical Polymerization Using Rationally Engineered Chain-End Capping Agents

使用合理设计的链封端剂开发立体定向受控/活性自由基聚合

• 批准号: 2108681
• 负责人: Mingjiang Zhong
• 金额: $ 45万
• 依托单位: Yale University
• 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: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108681&HistoricalAwards=false
• 关键词: Development; Stereospecific; Controlled; Living; Radical

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Mingjiang Zhong of Yale University will develop new methods for the efficient preparation of polymers with control of stereochemistry. Stereochemistry of polymers originates from the orientation of pendant groups attached to the main backbone and has a significant influence on important materials properties, including mechanical stiffness, toughness, thermal behavior, crystallinity, and solubility. Tuning the stereochemistry of polymers can dramatically change the properties and therefore can lead to new applications of many polymers. However, currently existing methods to achieve control over stereochemistry are somewhat limited in scope; there is room for new methods development. This project aims to establish methods that are compatible with a broader scope of building blocks compared to traditional approaches, that can be carried out in environmentally friendly solvents, and that provide pathways for stereocontrolled access to new functional materials. The research activities affiliated with this project are expected to have broader scientific impact in the synthesis of mechanically robust materials, as well as materials with important biomedical uses. The associated teaching, mentoring, and outreach activities will create educational opportunities for a diverse group of trainees.This project proposes new approaches to synthesizing isotactic polymers via radical polymerization. Lewis acid-tethered stable radical species will be synthesized to control polymer tacticity via confined chain end conformation in controlled/living radical polymerizations. An array of stable radical species will be explored, across a range of reaction solvents and tethered ligands with the goal of expanding the space of polymerizable monomers. The Zhong research team will also investigate polymerization mechanisms with the aim of developing a deeper understanding of this catalytic system. Among the mechanistic features to be examined are included Lewis acid coordination to monomer units, chain end conformation during radical addition, and the kinetics and thermodynamics of the radical deactivation process. The successful development and deployment of these catalysts would be significant, particularly because they have the potential to provide a new approach to the important problem of stereocontrol in radical addition. This research also has potential industrial chemical implications due to the advantages of radical polymerization over polymerization conditions that require acidic or basic conditions, with radical polymerization approaches generally exhibiting greater functional group tolerance and milder reaction conditions.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.

在化学系大分子、超分子和纳米化学项目的支持下，耶鲁大学钟明江将开发新的方法，在立体化学控制下高效地制备聚合物。聚合物的立体化学源于主链上侧基的取向，对材料的力学性能、韧性、热性能、结晶度和溶解性等有重要影响。调节聚合物的立体化学可以极大地改变聚合物的性质，因此可以导致许多聚合物的新应用。然而，目前实现立体化学控制的现有方法在范围上有所限制；新方法有开发的空间。该项目旨在建立与传统方法相比，与更大范围的构建块相兼容的方法，这些方法可以在环境友好的溶剂中进行，并为获得新的功能材料提供立体控制的途径。与该项目相关的研究活动预计将在机械坚固材料的合成以及具有重要生物医学用途的材料的合成方面产生更广泛的科学影响。相关的教学、指导和推广活动将为不同的受训者创造教育机会。这个项目提出了通过自由基聚合合成全同立构聚合物的新方法。在可控/活性自由基聚合中，将通过限制链端构象来合成Lewis酸连接的稳定自由基物种来控制聚合物的规整性。将探索一系列稳定的自由基物种，跨越一系列反应溶剂和连接配体，目标是扩大可聚合单体的空间。钟研究小组还将研究聚合机理，目的是加深对这一催化体系的了解。要考察的机理特征包括单体单元的Lewis酸配位，自由基加成过程中的链端构象，以及自由基失活过程的动力学和热力学。这些催化剂的成功开发和部署将具有重要意义，特别是因为它们有可能为自由基加成中立体控制这一重要问题提供一种新的方法。这项研究还具有潜在的工业化学影响，因为与需要酸性或碱性条件的聚合条件相比，自由基聚合方法具有更大的官能团容忍度和更温和的反应条件。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Rare earth–cobalt bimetallic catalysis mediates stereocontrolled living radical polymerization of acrylamides

稀土-钴双金属催化介导丙烯酰胺立体控制活性自由基聚合

• DOI: 10.1038/s44160-023-00311-9
• 发表时间: 2023
• 期刊: Nature Synthesis
• 作者: Zhang, Xiaowei;Lin, Fei;Cao, Mengxue;Zhong, Mingjiang
• 通讯作者: Zhong, Mingjiang