Exploring new experimental space with inversely-polarized phosphaalkenes and dianionic pincer ligands

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Double bonds play a crucial role in synthetic chemistry. Simple olefins, such as ethylene, propylene, acrylates and other related functionalized olefins are important building blocks for the polymer industry. The reactivity of C=C double bonds can also undergo alkene metathesis (and alkyne metathesis for CC triple bonds) to create new value-added chemicals and materials used across the industry, from fine chemicals to perfumes, pharmaceuticals and polymers. Similarly, polar double bonds such as C=O and C=N are hydrogenated into high-value molecules, with the possibility to introduce a new chiral centre in the molecule with biological activity. Developing a solid fundamental understanding of catalysis is essential for the industry to have access to better (more stable, more active and more selective) catalysts that can mediate important transformations with a wide range of substrates. ******The proposed research program will allow us to explore and demonstrate the scope and utility of two classes of ancillary ligands that have remained largely unexplored in homogeneous catalysis: inversely-polarized phosphaalkenes and dianionic pincer (XLY2) ligands. These will be investigated in the context of olefin metathesis, polymerization, double bond hydrogenation and water oxidation. Both classes of ligands offer tremendous opportunities to impact the field of catalysis in general, as tertiary phosphines, N-heterocyclic carbenes and monoanionic pincer ligands have in the past decades. They ligands open up new unexplored experimental space, while providing remarkable control over the sterics and electronics about the metal. In the course of the program, the coordination chemistry of cobalt will be extensively studied to expand the use of this earth-abundant metal in catalytic transformations often dominated by more expensive and rare precious metals. The study of these well-defined transition metal complexes will provide valuable fundamental knowledge and great insight into critically-important catalytic transformations, including water oxidation.