CAREER: Olefin Polymerization Catalysts with Ligands Featuring Weakly Coordinating Carborane Anions

在这个由化学部门化学催化项目资助的项目中，加州大学河滨分校的Vincent Lavallo教授正在开发新的催化剂，能够将烯烃原料转化为具有独特和理想性能的聚合物。聚合物是长链有机分子，在日常生活的许多方面都使用塑料，包括食品包装，汽车和航空航天运输的结构材料，以及轻质电子设备。制备有用的聚合物，如塑料，需要使用催化剂来促进链构建过程并控制随后材料的物理性质。Lavallo教授正在开发一种催化剂，这种催化剂含有一种被称为碳硼烷阴离子的硼和碳原子的新集合，预计这种阴离子将赋予催化剂独特的性能。加州大学河滨分校化学系的本科生和研究生在这个项目中接受指导并参与研究。拉瓦洛教授还在为来自经济困难背景的高中生制定一个指导计划。在夏季的几个月里，这些高中生将参与UCR的拟议研究，在学年期间，高中将实施新的课程，让大量学生直接参与到项目中来。在这个项目中，Lavallo教授正在合成和研究含有二十面体碳硼烷阴离子取代基的膦和n杂环碳烯配体。二十面体碳硼烷阴离子远比磺酸盐配位更弱，碱性更弱，体积更大（膦磺酸盐的钯配合物是一种不寻常的烯烃聚合催化剂，主要产生线性聚乙烯共聚物），这些性质应该有利于催化所需的反式配合物的形成，也抑制了β的消除。目标是生产具有增强活性、官能团耐受性的烯烃聚合催化剂，并与最先进的体系相比，生产具有更高均匀性和分子量的聚合物。该项目的更广泛影响涉及磷化氢和含有二十面体碳硼烷阴离子取代基的n -杂环碳配体的潜在用途，以及计划的针对经济背景较差的高中生的教育活动。

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Vincent Lavallo of the University of California at Riverside is developing new catalysts capable of converting olefin feedstocks into polymers with distinct and desirable properties. Polymers are long chain organic molecules and are found in many facets of everyday life that utilize plastics, including food packaging, structural materials for automotive and aerospace transportation, and lightweight electronic devices. The preparation of useful polymers, such as plastics, requires the utilization of a catalyst to facilitate the chain building process and control the physical properties of the ensuing material. Professor Lavallo is developing catalysts that contain a novel collection of boron and carbon atoms called a carborane anion, which is predicted to bestow unique properties upon the catalysts. Undergraduate and graduate students in the Chemistry Department at the University of California Riverside are being mentored in this program and are participating in the research. Professor Lavallo is also developing a mentorship program for high school students from economically disadvantaged backgrounds. In the summer months, these high school students will participate in the proposed research at UCR, and during the academic year, a novel curriculum will be implemented at the high school, allowing a large number of students to directly engage in the project. In this project, Professor Lavallo is synthesizing and studying phosphine and N-heterocyclic carbene ligands containing icosahedral carborane anion substituents. Icosahedral carborane anions are far more weakly coordinating, less basic, and larger than sulfonates (palladium complexes of phosphine-sulfonates are an unusual family of olefin polymerization catalysts that produce mostly linear polyethylene copolymers), and these properties should favor the formation of the trans-pi-complexes necessary for catalysis and also inhibit beta-elimination. The objective is to produce olefin polymerization catalysts that display enhanced activity, functional group tolerance, and produce polymers with greater uniformity and molecular weight compared to state-of-the-art systems. The broader impacts of the project pertain to the potential uses of phosphine and N-heterocyclic carbene ligands containing icosahedral carborane anion substituents and the planned educational activities targeted towards high school students from economically disadvantaged backgrounds.