Mechanistic Investigations of Olefin Polymerizations and Selective Oligomerizations

这一无机化学、生物无机化学和金属有机化学项目的研究奖支持马里兰大学帕克分校的劳伦斯·R·西塔教授的工作，他研究了分子上定义明确的过渡金属络合物介导的1-烯烃的配位聚合和选择性齐聚机理。新的动态和可逆的双分子过程与一级链增长传播具有竞争性，正在被识别和建立为机械控制点，通过这些控制点，只使用一个催化剂就可以在两种限制材料之间生产不同牌号的聚烯烃的近连续统。当与活性配位链转移聚合相结合时，有望实现这些新型聚烯烃材料的实际商业规模。所支持的工作进一步提供了一个重要的工具，将通过它开展外联活动，教育普通公众了解全球聚烯烃工业和相关研究的当前需求、限制和影响。进行研究的学生接受化学基础和实用两方面的培训，并将为进入劳动力大军做好充分准备。文明和我们所知的生活质量完全依赖于通过使用主要以经验方式发现的催化剂，通过乙烯、丙烯和更高级的1-烯烃的配位聚合而制备的“塑料”材料。对控制这些催化剂的机械过程的详细研究可以提供新的和变革性的策略，通过这些策略可以大大增加塑料材料的范围，同时大幅缩短研发周期。

This Research award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports work by Professor Lawrence R. Sita at the University of Maryland, College Park to investigate mechanisms for the coordination polymerization and selective oligomerization of 1-alkenes as mediated by molecularly-well-defined transition metal complexes. Novel dynamic and reversible bimolecular processes that are competitive with first-order chain-growth propagation are being identified and established as mechanistic control points by which the production of a near continuum of different polyolefin grades between two limiting materials can be accomplished using only a single catalyst. When combined with living coordination chain-transfer polymerization, it is anticipated that practical commercial volumes of these new polyolefin materials can be realized. The supported work further provides a critical vehicle through which outreach activities will be conducted to educate the general public regarding the current needs, limitations, and impact of the global polyolefins industry and related research. Students conducting the studies receive training in both fundamental and practical apsects of chemistry and will be well prepared to enter the workforce.Civilization and the quality of life as we know it is wholly dependent upon "plastic" materials prepared through the coordination polymerization of ethene, propene, and higher 1-alkene using catalysts that are largely discovered in empirical fashion. Detailed investigations of mechanistic processes that govern these catalysts can provide new and transformational strategies by which the range of plastic materials can be greatly increased while dramatically reducing the research and development cycle.