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

在这个由化学部化学催化计划资助的项目中，加州大学滨江分校的Vincent Lavallo教授正在开发能够将烯烃原料转化为具有独特和理想性能的聚合物的新催化剂。 聚合物是长链有机分子，存在于日常生活中使用塑料的许多方面，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。 有用的聚合物如塑料的制备需要利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。 加州大学滨江化学系的本科生和研究生正在接受这一方案的指导，并参与这项研究。Lavallo教授还为来自经济困难背景的高中生开发了一个导师计划。在夏季的几个月里，这些高中生将参加UCR的拟议研究，并在学年期间，一个新颖的课程将在高中实施，让大量的学生直接参与该项目。 在这个项目中，Lavallo教授正在合成和研究含二十面体碳硼烷阴离子取代基的膦和N-杂环卡宾配体。 二十面体碳硼烷阴离子远比磺酸盐更弱配位、碱性更小且更大（膦磺酸盐的钯络合物是烯烃聚合催化剂的不寻常家族，其产生主要为线性聚乙烯共聚物），并且这些性质应有利于形成催化所需的反式-π-络合物并且还抑制β-消除。 目的是生产烯烃聚合催化剂，该催化剂显示出增强的活性、官能团耐受性，并且生产与现有技术体系相比具有更大均匀性和分子量的聚合物。 该项目的更广泛影响涉及含有二十面体碳硼烷阴离子取代基的膦和N-杂环卡宾配体的潜在用途，以及计划针对经济困难背景的高中生开展的教育活动。

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.