CAREER: Binucleating Bis(pyrazolyl)alkanes for Tractable Bimetallic Polymerization

在化学系化学催化项目的支持下，休斯顿大学的Robert Comito正在开发用于合成可生物降解聚合物的催化剂。目前，大多数合成塑料和弹性体是由石油化工产品制备的，既不能生物降解，也不能生物相容。虽然已经开发了一些可生物降解的聚合物作为石化聚合物的替代品，但它们的合成需要与用于石化产品的催化剂不同的催化剂，这些催化剂还不清楚。Comito研究计划的目标是通过关注多个金属位点之间的合作，开发用于生物降解聚合物合成的催化剂的新平台。这些研究的重点是寻找新的催化剂，可以调整，以制备具有新的结构，新的物理性能和改进的性能的生物可降解聚合物。这些活动正在进一步用于培训有机金属化学，催化和聚合物合成方面的各类学生，重点是纳入本科生，第一代学者和STEM（科学，技术，工程和数学）学科中代表性不足的群体。此外，通过该研究项目产生的技术知识被转化为公开的教育材料，用于向研究生教授机理分析，向本科生教授反应机理。在该奖项下，Robert Comito和他的研究团队正在开发两种主族金属近端配位的配体，用于协同催化可生物降解聚合物的可控合成。本研究的基本假设是主族金属催化酯和碳酸酯聚合不可避免地涉及多金属机理。考虑到醇盐链端的金属桥接配位和单体原料的双官能插入是聚合过程中链增长的基本特征，Comito和他的小组正在评估相邻催化金属位点的取向、距离和取代，以确定产生独特聚合物结构的主基催化聚合的控制机制特征。Comito博士将这些技能应用于教学中的机械分析，正在制作拖放式教材，以改善数字格式的反应机制教学。他还编写了关于控制实验的教学材料，这是一类对理解科学机制至关重要的实验，但很少在课堂上教授。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

With the support of the Chemical Catalysis Program in the Division of Chemistry, Robert Comito of the University of Houston is developing bimetallic catalysts for the synthesis of biodegradable polymers. Currently, most synthetic plastics and elastomers are prepared from petrochemicals and are neither biodegradable nor biocompatible. Although some biodegradable polymers have been developed as replacements for petrochemical ones, their synthesis requires different catalysts than those used for petrochemicals that are not well understood. The goal of the Comito research program is to develop a new platform of catalysts for biodegradable polymer synthesis by focusing on the cooperation between multiple metal sites. These studies are focused on finding new catalysts that can be tuned to prepare biodegradable polymers with novel structures, new physical properties, and improved performance. These activities are further being used to train a diverse group of students in organometallic chemistry, catalysis, and polymer synthesis with emphasis on the inclusion of undergraduates, first-generation scholars, and underrepresented groups in STEM (science, technology, engineering and mathematics) disciplines. Moreover, the technical knowledge generated through this research program is being converted into publicly available educational materials for teaching mechanistic analysis to graduate students and reaction mechanisms to undergraduates.Under this award, Robert Comito and his research team are developing ligands for the proximal coordination of two main group metals for cooperative catalysis toward the controllable synthesis of biodegradable polymers. The hypothesis underlying this research program is that the catalytic polymerization of esters and carbonates by main group metals inevitably involves multi-metallic mechanisms. Considering that metal-bridging coordination of an alkoxide chain end and bifunctional insertion of the monomer feedstock are essential features of chain growth during polymerization, Comito and his group are evaluating the orientation, distance, and substitution of adjacent catalytic metal sites to identify the controlling mechanistic features of main-group catalyzed polymerization that produce unique polymer structures. Applying these skills in mechanistic analysis toward teaching, Dr. Comito is generating drag-and-drop teaching materials that will improve the instruction of reaction mechanisms in a digital format. He is also generating pedagogical materials on control experiments, a class of experiments essential toward understanding mechanisms in science but which are rarely taught in the classroom.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.