Reactive Cationic Zr(IV) and Ti(IV) Complexes Containing Labile Ligands

含有不稳定配体的反应性阳离子 Zr(IV) 和 Ti(IV) 配合物

• 批准号: 8816445
• 负责人: Richard Jordan
• 金额: $ 10万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-15 至 1990-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8816445&HistoricalAwards=false
• 关键词: Reactive; Cationic; Zr; IV; Ti

Ziegler-Natta catalysts are used widely as industrial catalysts for the synthesis of polymers. The zirconium and titanium compounds which will be studied in this project are related to soluble Ziegler-Natta catalysts. This project is expected to provide a better understanding of how these catalysts function and to provide information needed to design more specific and more efficient catalysts for polymer synthesis. General methods for the synthesis and isolation of cationic organozirconium complexes of the type bis-Cp-Zr(R)(L) where L is a labile ligand have been discovered. The organozirconium complexes are highly reactive. Their Zr-R bonds undergo rapid insertion of ketones, nitriles and other polar unsaturated substrates, and the THF complexes polymerize ethylene in the absence of an A1 cocatalyst. These observations support recent proposals that cationic Ti and Zr complexes are active species in soluble Ziegler-Natta catalyst systems. The cationic organozirconium complexes are also easily hydrogenated to synthetically useful cationic hydrides. The research plan is to synthesize an extensive series of Cp2M(R)(L) complexes (M = Ti, Zr) and to study the scope and mechanisms of their reactions with olefins and other unsaturated substrates, and with hydrogen. These novel compounds provide an opportunity to study the fundamental features of insertion reactions of M-R bonds (M = Ti, Zr) in the absence of the many complications caused by A1 cocatalysts. Also included in this project is research to develop asymmetric organic syntheses based on chiral cationic Cp2M(R)(L) complexes.

Ziegler-Natta催化剂被广泛用作合成聚合物的工业催化剂。本项目将研究的锆钛化合物与可溶性Ziegler-Natta催化剂有关。该项目有望更好地了解这些催化剂的功能，并提供为聚合物合成设计更具体和更有效的催化剂所需的信息。发现了合成和分离双-Cp-Zr(R)(L)型阳离子有机锆络合物的一般方法，其中L是一个不稳定的配体。有机锆络合物具有很高的活性。它们的Zr-R键可以快速插入酮、腈和其他极性不饱和底物，THF络合物在没有A1助催化剂的情况下聚合乙烯。这些观察结果支持最近的观点，即阳离子钛和锆络合物是可溶性Ziegler-Natta催化剂体系中的活性物种。阳离子有机锆络合物也很容易氢化成合成有用的阳离子氢化物。本研究计划合成一系列Cp2M(R)(L)配合物(M=Ti，Zr)，并研究它们与烯烃等不饱和底物以及与氢反应的范围和机理。这些新化合物为研究M-R键插入反应的基本特征提供了一个机会，而不存在A1助催化剂引起的许多复杂情况。本项目还包括开发基于手性阳离子Cp2M(R)(L)配合物的不对称有机合成的研究。