Transition Metal-Catalyzed Olefin Polymerization: Mechanistic Studies and Catalyst Design

最重要的工业过程之一是 烯烃，即含烃分子的转化 双键，聚合物。两种这样的聚合物的实例是 聚乙烯和聚丙烯。虽然有机金属 催化剂已经用于工业聚合， 几十年来，人们对烯烃的了解非常少， 关于催化过程的详细机制，以及 催化剂设计主要是经验性的。校长 研究人员已经开发出一种化学方法， 烯烃聚合的机理细节，并允许更多 催化剂系统的逻辑设计。 过渡金属烷基烯烃的迁移插入反应 复合物是异质和同质的关键转变 烯烃聚合反应和许多化学计量 碳-碳键形成反应。拟议的工作重点 了解这个反应的基本方面， 新烯烃聚合的制备和研究 催化剂的主要研究者已获得结果 最近的研究表明， 乙烯氢化物配合物的结构和动力学 烷基类似物和存在的乙烯氢化物络合物 作为桥连或无规结构可以作为乙烯 聚合催化剂一种钴配合物， 发现了一个能催化活性 乙烯聚合。本研究的目的是（1） 合成和探索的反应性和催化活性的 含阳离子和中性Co（III）配合物 乙基，中性或阴离子双电子供体基团，和 Cp或Cp* 配体，（2）制备新的Agostic 乙烯氢化物络合物，并将这些物质评价为烯烃 聚合催化剂，（3）开发这些新的配合物 用于各种烯烃的活性聚合， 强调聚合物的机械特性的相关性 构造和利用生活系统， 共聚，以及4）开发官能化或 用官能基封端聚合物链的一端或两端， 组

One of the most important industrial processes is the conversion of olefins, i.e. hydrocarbon molecules containing double bonds, to polymers. Examples of two such polymers are polyethylene and polypropylene. Although organometallic catalysts have been used in the commercial polymerization of olefins for several decades, remarkably little is understood about the detailed mechanism of the catalytic processes, and catalyst design has been largely empirical. The Principal Investigator has developed chemistry which promises to yield mechanistic details of olefin polymerization and allow more logical design of catalyst systems. Migratory insertion reactions of transition metal alkyl olefin complexes are key transformations in hetero- and homogeneous olefin polymerization reactions and numerous stoichiometric carbon-carbon bond forming reactions. The proposed work focuses on understanding fundamental aspects of this reaction coupled with preparation and study of new olefin polymerization catalysts. The Principal Investigator has obtained results recently which suggest that there is a relationship between the structure and dynamics of ethylene hydride complexes and their alkyl analogs and that ethylene hydride complexes which exist as bridged or agostic structures can serve as ethylene polymerization catalysts. A cobalt complex possessing an agostic ethyl group has been discovered which catalyzes living polymerization of ethylene. Goals of the research are (1) to synthesize and explore the reactivity and catalytic activity of cationic and neutral Co(III) complexes containing an agostic ethyl group, a neutral or anionic two-electron donor group, and either a Cp or a Cp* ligand, (2) to prepare new agostic ethylene hydride complexes and evaluate these species as olefin polymerization catalysts, (3) to develop these new complexes for living polymerization of a diverse group of olefins, with emphasis on correlations of mechanistic features with polymer structure and utilizing living systems for block and copolymerization, and 4) to develop methods to functionalize or cap one or both ends of the polymer chain with functional groups.