N-heterocuclic carbene metal complexes

用于烯烃聚合的均相过渡金属催化剂的开发是化学家如何将其在分子水平上的反应如何进行的知识转化为大规模工业应用的完美例子。现在有许多催化剂可以用来以受控的方式聚合乙烯和其他简单的单体，如丙烯或苯乙烯，以得到具有非常规则的分子结构的聚合物。这种对聚合物微结构的控制导致材料具有高度定制的性能。然而，这些聚合物往往缺乏只有带有官能团的聚合物才具有的重要性能，如韧性、结晶度、气体渗透性和改善的可染性。不幸的是，到目前为止还没有可以接受的催化剂来控制这种聚合物的结构。这些催化剂在聚合物构建块本身存在的情况下活性较差，或者在反应条件下简单地分解。因此，需要开发耐热的新催化剂，并且能够在与商业相关的工艺条件下(即，高温和压力)以高速率生产这种功能聚合物。我的团队开发了新的催化剂来解决这些限制。到目前为止，我们已经开发了四种新的催化剂。对它们在乙烯聚合中的催化活性进行了评估，初步结果为我们提供了如何提高它们的活性的见解。我们在本申请中提出的工作旨在通过仔细改变这些催化剂的化学结构来进一步改进这些催化剂，从而建立结构-性能关系，从而获得更好的催化剂。除了继续我们对迄今制备的四类催化剂的研究外，我们还根据文献报道的工作提出了第五类催化剂。我们正在研究的化合物具有其他催化转化所涉及的化合物的共同特征，包括交叉偶联反应，这是2010年诺贝尔化学奖的基础。因此，我们的工作产生的结果将影响其他重要的研究领域。

The development of homogeneous transition metal catalysts for olefin polymerization is the perfect example of how chemists have been able to translate their knowledge of how reactions proceed at the molecular level into large-scale industrial applications. Many catalysts are now available to polymerize ethylene and other simple monomers, such as propylene or styrene, in a controlled manner to give polymers that have a very regular molecular structures. This control over the polymer microstructure leads to materials with highly tailored properties. However, these polymers often lack important properties, such as toughness, crystallinity, gas impermeability and improved dyeability, that only polymers with functional groups possess. Unfortunately, no acceptable catalyst to date exists to control the structure of such polymers. These catalysts suffer from poor activity in the presence of the polymer building-blocks themselves, or simply decompose under reaction conditions. There is thus a need to develop new catalysts that will be thermally robust and that will be able to produce such functional polymers at high rates under commercially-relevant process conditions (i.e., high temperatures and pressures). My group develops new catalysts to address those limitations. We have so far developed four new classes of catalysts. Their catalytic activity in ethylene polymerization has been assessed and preliminary results have given us insights into how to improve their activity. The work that we are proposing in this application aims at further improving these catalysts by carefully changing their chemical structure and as a result, establishing structure-property relationships that will lead to even better catalysts. In addition to continuing our work on the four classes of catalysts prepared so far, we are proposing a fifth class of catalysts that hold promise based on work reported in the literature. The compounds that we are investigating have features that are common to those involved in other catalytic transformations, including cross-coupling reactions, which is the basis of the 2010 Nobel Prize in chemistry. As such, the findings generated by our work will impact other important areas of research.