Zirconium-Allyl Complexes as Intermediates in Zirconocene-Catalyzed Olefin Polymerizations

该项目的主要目标是：1.澄清参与茂锆催化的烯烃聚合的锆烯丙基络合物的分子结构和合适的模型络合物；2.评估锆烯丙基络合物的形成速度和程度与茂锆配体结构以及活化和聚合条件的关系；3.阐明导致锆烯丙基络合物形成、异构化、进一步聚合链增长和链增长终止的反应路径。关于基本催化过程的见解应结合关于聚合动力学、聚合物产物的摩尔质量和微观结构以及其他链端频率的现象学观察来提出。

Main objectives of the proposed project are:1. clarification of the molecular structures of zirconium-allyl complexes, which participate in zirconocene-catalyzed olefin polymerization and of suitable model complexes;2. assessment of the rate and extent of zirconium-allyl complex formation in dependence of zirconocene ligand strucrures and of activation and polymerization conditions;3. elucidation of reaction paths which lead to the formation of zirconium-allyl complexes, to their isomerization, to further polymer-chain growth and to chain-growth termination.Insights thus obtained with regard to elementary catalysis processes are to be put in relation to phenomenological observations concerning e.g. polymerization kinetics, molar masses and microstructures of polymer products and alternative chain-end frequencies.