Pathway Control in Dynamic Covalent (DC) Synthesis

分子笼是一类独特的化合物，在催化、电池技术、过滤和分离等领域具有潜在的应用前景。这些单分子具有三维形状，大小可变，内部有空白空间。构建分子笼和其他形状保持结构最有效的方法是被称为动态共价化学(DCC)的合成过程。使用DCC意味着化学家可以用简单的前体建立结构，这些结构在单个化学反应过程中“自组装”成所需的几何形状，而不是在许多反应中逐步建立结构。然而，使用DCC时的一个主要挑战是很难预测哪种前体最适合获得所需的体系结构。目前，伊利诺伊大学厄巴纳-香槟分校的摩尔小组正在为DCC制定一套指导方针，这将有助于化学家设计更好的前体和合成策略来构建三维建筑。该项目支持未来研究人员和教育工作者的教育和专业发展，为科学和工程领域的劳动力做准备。此外，摩尔集团成员还参与公共宣传和教育活动(例如，鼓励为当地中学举办明天的化学家活动)，以交流和促进下一代强大的科学素养。在NSF大分子、超分子和纳米化学计划的支持下，Moore小组正在使用炔烃歧化作为模型DCC反应来研究交换率和产品分布之间的关系，特别是在已知形成动力学陷阱的情况下。DCC描述了可逆反应，其中分子组分可以自由交换，直到达到热力学最低值，当交换速率太慢和/或构建块具有较高的价态时，就会出现动力学陷阱。该团队的目标是建立一个计算模型，描述汇率、价位和产品分布之间的关系。计算模型的设计是为了让化学家更好地了解哪些DCC反应或反应条件是获得预测结构所必需的。此外，该模型还预测了在给定反应中何时可能出现动力学陷阱，以及可以预期的最大产物产率。计算模型补充了简单和复杂的炔烃歧化反应的实验动力学数据。一旦基础建立，它们将被用作访问更复杂的形状-纳米尺度的持久分子结构的指南。这一奖项反映了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。

Molecular cages are emerging as a unique class of compounds with potential applications in catalysis, battery technology, and filtrations and separations. These single molecules have three-dimensional shapes, variable sizes, and empty space in their interiors. The most efficient way to build molecular cages and other shape-persistent architectures is the synthetic process known as dynamic covalent chemistry (DCC). Using DCC means that chemists can build structures with simple precursors which "self-assemble" into the desired geometry over the course of a single chemical reaction rather than building structures step-by-step over many reactions. However, a major challenge when using DCC is the difficulty in predicting what precursor is best to obtain the desired architecture. Currently, the Moore group of the University of Illinois at Urbana-Champain is working toward a set of guidelines for DCC which will help chemists design better precursors and synthetic strategies for building three-dimensional architectures. This project supports the education and professional development for future researchers and educators, preparing for a workforce for the science and engineering fields. In addition, the Moore Group members participate in public outreach and educational activities (e.g., Encouraging Tomorrow's Chemists events for local middle schools) to communicate and promote a strong literacy in science for the next generation. With the support from the NSF Macromolecular, Supramolecular and Nanochemistry Program, the Moore group is using alkyne metathesis as a model DCC reaction to study the relationship between exchange rate and product distribution, especially in cases where kinetic traps are known to form. DCC describes reversible reactions where molecular components can exchange freely until a thermodynamic minimum is achieved, and kinetic traps arise when exchange rates are too slow and/or the building blocks have a high valance. The team aims to build a computational model that describes the relationship between exchange rates, valancy, and product distribution. The computational model is designed to provide chemists with a better understanding of which DCC reactions or reaction conditions are necessary to access predicted structures. Additionally, the model predicts when kinetic traps are likely to arise in a given reaction and the maximum product yield that can be expected. The computational model is supplemented with experimentally obtained kinetic data for both simple and complex alkyne metathesis reactions. Once the fundamentals are established, they will be used as a guide for accessing more complex shape-persistent molecular architectures of nanoscale dimension.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.