N-heterocuclic carbene metal complexes

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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.