CAS: Diastereoselective Polymerization Catalysis for Stereo-Sequenced Polymers with Biodegradability and Chemical Circularity

通过这一奖项，美国国家科学基金会化学部的化学催化计划正在支持科罗拉多州立大学化学系的Eugene Chen教授的研究。陈教授正在为合成先进的聚合物材料设计催化剂系统，这些材料是可生物降解的，化学上是循环的(可以分解成它们的组成部分)。该计划的中心目标是开发聚合催化剂，能够直接将单体非对映异构体(具有相同键连接但不同三维结构的分子)的混合物转化为具有明确三维结构的新型高性能生物降解材料。还在研究将聚合物解构成片段，这些片段可以重新连接成单体。这项工作正在开发新的催化工艺，用于原子和能源效率高的聚合物材料的合成。拟议的研究涵盖了化学科学、材料工程和可持续发展的不同领域，从而为培训和教授学生提供了一个极好的机会，包括代表性不足的学生和本科生。该项目还解决了提高聚合物可回收性的迫切需要，陈教授在研讨会、讲座和演讲中强调了这一可持续性问题的重要性。新型催化剂可以将任意RAc/介观比的非对映单体混合物聚合成立体有序聚合物，有可能改变高性能结晶材料的合成。非对映选择性聚合不仅避免了传统立体选择聚合方法所需的非对映异构体预分离和提纯所需的材料损失和额外的能量成本，而且还利用混合物中的所有非对映异构体来调节材料的性质。这项研究正在推进非对映选择性聚合催化，以实现非对映单体混合物的直接聚合，得到全同立构/间同立构的可生物降解结晶聚合物。该方法包括设计非对映异构体选择性和富含稀土的催化剂，以及通过实验和理论相结合的方法检查催化剂的结构-选择性关系。此外，合成聚合物的催化化学环性正在被开发，以将这些材料转化回它们的单体，从而关闭它们的生命周期。该项目采用合理的催化剂/单体设计方法，通过强调与双缩和非对映选择性相关的基本概念，推动聚合材料和方法的进步。这些研究为不同背景的有抱负的本科生、研究生和博士后化学家提供了极好的培训基础。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。

With this award, the Chemical Catalysis Program of the NSF Division of Chemistry is supporting the research of Professor Eugene Chen in the Department of Chemistry at Colorado State University. Professor Chen is designing catalyst systems for the synthesis of advanced polymeric materials that are biodegradable and chemically circular (can be deconstructed back into their component parts). The central goal of this program is to develop polymerization catalysts that can directly convert mixtures of monomer diastereomers (molecules that have the same bond connections but different three-dimensional structure) into new high-performance biodegradable materials with defined three-dimensional structure. Deconstruction of the polymers into fragments that can be joined back together into monomers is also being studied. This work is developing new catalytic processes for the atom- and energy-efficient synthesis of polymeric materials. The proposed research encompasses diverse areas of the chemical sciences, materials engineering, and sustainability, thereby providing an excellent opportunity for the training and teaching of students, including underrepresented and undergraduate students. This project also addresses the critical need to improve polymer recyclability and Professor Chen is emphasizing the importance of this sustainability issue in workshops, lectures, and presentations. New catalysts that can polymerize diastereomeric mixtures of monomers at any rac/meso ratio into stereo-sequenced polymers have the potential to transform the synthesis of high-performance crystalline materials. Diastereoselective polymerization not only avoids the material loss and added energy costs associated with diastereomeric pre-separation and purification required by traditional stereoselective polymerization methods, but also utilizes all of the diastereomers in a mixture to modulate material properties. This study is advancing diastereoselective polymerization catalysis to achieve direct polymerization of diastereomeric monomer mixtures into isotactic/syndiotactic stereo-sequenced biodegradable crystalline polymers. The approach involves designing diastereomer-selective and earth-abundant catalysts as well as examining catalyst structure–selectivity relationships via a combined experimental and theoretical approach. Furthermore, catalysis-enabled chemical circularity of the synthesized polymers is being developed to transform these materials back to their monomers, thus closing the loop of their life cycles. This program uses a rational catalyst/monomer design approach to advance polymeric materials and methodologies by emphasizing fundamental concepts related to ditacticity and diastereoselectivity. These studies serve as an excellent training ground for aspiring undergraduate, graduate, and postdoctoral chemists of diverse backgrounds.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.