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

在化学系化学催化项目的支持下，休斯顿大学的罗伯特·科米托正在开发用于合成可生物降解聚合物的双金属催化剂。目前，大多数合成塑料和弹性体都是从石化产品中制备的，既不能生物降解，也不能生物兼容。尽管一些可生物降解的聚合物已经被开发出来作为石化聚合物的替代品，但它们的合成需要不同于那些用于石化的催化剂，这些催化剂还没有被很好地理解。Comito研究计划的目标是通过关注多个金属位置之间的合作来开发一种新的可生物降解聚合物合成催化剂平台。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。这些活动还被进一步用于培训不同的学生群体，包括有机金属化学、催化和聚合物合成，重点是纳入STEM(科学、技术、工程和数学)学科的本科生、第一代学者和代表性较低的群体。此外，通过这项研究计划产生的技术知识正在转化为公开可用的教材，用于向研究生教授机械分析，向本科生讲授反应机理。在这一奖项下，Robert Comito和他的研究团队正在开发用于两个主要族金属的近邻配位的配体，用于合作催化可生物降解聚合物的可控合成。这项研究计划背后的假设是，主族金属催化酯类和碳酸盐聚合不可避免地涉及多金属机制。考虑到醇链末端的金属桥联配位和单体原料的双官能团插入是聚合过程中链增长的基本特征，Comito和他的团队正在评估邻近催化金属中心的取向、距离和取代，以确定主基催化聚合的控制机理特征，从而产生独特的聚合物结构。科米托博士将机械分析中的这些技能应用到教学中，他正在制作拖放式教材，这将以数字形式改进反应机制的教学。他还编写了关于对照实验的教学材料，这类实验对于理解科学中的机制至关重要，但很少在课堂上教授。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。

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.