Mechanistic Investigations of Olefin Polymerizations and Selective Oligomerizations

无机化学、生物无机化学和金属有机化学项目的这一奖项支持马里兰大学学院公园分校的Lawrence B.Sita教授的研究，他使用单环戊二烯、酰胺化配体组合来为各种含有β-氢的早期过渡金属烷基化合物提供显著的动力学稳定性。主要目的是利用中性和阳离子基团4和5单环戊二烯、单酰胺金属烷基化合物作为手段来研究Ziegler-Natta聚合以及乙烯和α-烯烃的高选择性三聚反应的机理。这项工作旨在确定如何利用分子内和分子间的动态过程来扩大可通过Ziegler-Natta过程制备的聚烯烃材料的结构和微观结构范围。这项工作将测试和验证一种新的范式，通过基于简并转移活性Ziegler-Natta聚合的两态双分子控制来获得广泛的聚烯烃微结构。对于α-烯烃的选择性齐聚，建议的研究将有助于理解能够在新一代催化剂中实现更高活性和选择性的因素。这项工作的更广泛影响是可能开发更高效的催化剂和新的聚烯烃材料，这将对世界经济和社会都有利。拟议的工作将提供一个重要的载体，通过它，未来一代的本科生、研究生和博士后研究人员可以在考虑到促进多样性的情况下进行培训。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Lawrence B. Sita at the Univesity of Maryland at College Park to use a monocyclopentadienyl, amidinate ligand combination to impart significant kinetic stability to a variety of early transition metal alkyl complexes bearing beta-hydrogens. The primary objectives are to utilize neutral and cationic group 4 and 5 monocyclopentadienyl, monoamidinate metal alkyl complexes as a means to investigate mechanistic aspects of Ziegler-Natta polymerization and the highly selective trimerization of ethylene and alpha-olefins. This work seeks to determine how intra- and intermolecular dynamic processes can be harnessed to expand the structural and microstructural range of polyolefin materials that can be prepared through the Ziegler-Natta process. The work will test and validate a new paradigm for accessing a wide range of polyolefin microstructures through two-state bimolecular control that is based on degenerative-transfer living Ziegler-Natta polymerization. For the selective oligomerization of alpha-olefins, the proposed studies will contribute to an understanding of the factors that can serve to achieve both higher activities and selectivities in a new generation of catalysts. The broader impact of this work is the potential development of more efficient catalysts and new polyolefin materials that will be beneficial to both the world economy and society. The proposed work will provide an important vehicle by which future generations of undergraduates, graduate students, and postdoctoral researchers can be trained with the promotion of diversity in mind.