Mechanistic Investigations of Olefin Polymerizations and Selective Oligomerizations

这个无机、生物无机和有机金属化学项目的奖项支持马里兰大学帕克分校的Lawrence B. Sita教授的研究，该研究使用单环戊二烯基、氨基酸盐配体组合来赋予各种早期过渡金属烷基配合物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，单酰胺金属烷基配合物作为一种手段，研究齐格勒-纳塔聚合和乙烯和α -烯烃的高选择性三聚化的机制方面。这项工作旨在确定如何利用分子内和分子间动力学过程来扩大聚烯烃材料的结构和微观结构范围，这些聚烯烃材料可以通过齐格勒-纳塔工艺制备。这项工作将测试和验证一种新的范例，通过基于简并转移活Ziegler-Natta聚合的双态双分子控制来获得广泛的聚烯烃微观结构。对于α -烯烃的选择性寡聚化，拟议的研究将有助于了解可以在新一代催化剂中实现更高活性和选择性的因素。这项工作的更广泛的影响是可能开发出更有效的催化剂和新的聚烯烃材料，这将有利于世界经济和社会。拟议的工作将提供一个重要的工具，通过它，未来几代本科生、研究生和博士后研究人员可以培养出促进多样性的思想。

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.