Metal-Catalyzed Diene and Olefin Polymerizations: Mechanistic Studies and Catalyst Design

无机化学、生物无机化学和金属有机化学计划的这一奖项支持北卡罗来纳大学教堂山分校的Maurice Brookhart博士的研究，他利用裸烯丙基镍和(二烯)镍(烯丙基)+物种研究二烯聚合反应的机理。这两个物种在低温下都是高度活性的，是二烯聚合的关键中间体。这些镍“无配体”络合物以及单配位络合物和钯类似物将用于丁二烯和一系列取代二烯的聚合，并充分阐明这些聚合的机理细节，以确定允许控制聚二烯微结构的因素。将寻求活性聚合，以产生一系列包含具有潜在新结构和性能的官能团的共聚物。这些独特的裸M(烯丙基)+物种的反应性也将被探索与其他不饱和分子，包括烯烃、张力环烯烃和炔烃。其他项目包括(A)开发通过将乙烯齐聚与使用N2O的氧化链转移过程相结合来直接合成烷基醛的方法，以及(B)与鲍登学院的R.Broene合作的项目，以开发用于将α-烯烃二聚为线性α-烯烃二聚体的催化剂。通过与杜邦的长期合作，该实验室在新型聚合催化剂方面的最新发现正在走向商业化。来自理科少数族裔的本科生将被纳入这项研究。参与该项目的研究生还通过北卡罗来纳大学赞助的“星期六学院”积极参与到高中的宣传活动中。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry Program supports research by Dr. Maurice Brookhart at the University of North Carolina at Chapel Hill to examine the mechanism of diene polymerization reactions by using naked allyl-Ni species and (diene)Ni(allyl)+ species. Both species are highly reactive at low temperature and are key intermediates in diene polymerizations. These Ni "ligandless" complexes along with monoligated complexes and Pd analogs will be used to polymerize butadiene and a series of substituted dienes and to fully elucidate the mechanistic details of these polymerizations so as to identify factors that allow control of the polydiene microstuctures. Living polymerizations will be sought in order to generate a series of copolymers incorporating functional groups with potential new structures and properties. The reactivity of these unique naked M(allyl)+ species will also be explored with other unsaturated molecules including olefins, strained cyclic olefins and alkynes. Other projects include (a) developing a direct synthesis of alkyl aldehydes through combining ethylene oligomerization with an oxidative chain transfer process using N2O and (b) a collaborative project with R. Broene of Bowdoin College to develop catalysts for dimerization of alpha-olefins to the linear alpha-olefin dimers. Through a long-established collaboration with DuPont, recent discoveries from this laboratory on new polymerization catalysts are being brought towards commercialization. Undergraduate students from underrepresented minorities in science will be brought into the research. Graduate students involved in the project are also actively involved in outreach to high schools through the UNC-sponsored "Saturday Academy".