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

双键在合成化学中起着关键作用。简单烯烃，如乙烯、丙烯、丙烯酸酯和其他相关的功能化烯烃是聚合物工业的重要组成部分。C=C双键的反应性也可以进行烯烃复分解（和CC三键的炔复分解），以创造新的增值化学品和材料，用于整个工业，从精细化学品到香水，制药和聚合物。类似地，极性双键如C=O和C=N氢化成高价值分子，有可能在分子中引入具有生物活性的新手性中心。要想获得更好（更稳定、更活跃、更有选择性）的催化剂，从而在广泛的底物中介导重要的转化，对催化学有一个坚实的基础理解是至关重要的。提出的研究计划将使我们能够探索和展示两类辅助配体的范围和效用，这两类配体在均相催化中仍未得到很大程度的探索：反极化磷酸烯烃和二阴离子螯合体（XLY2）配体。这些将在烯烃复分解、聚合、双键加氢和水氧化的背景下进行研究。这两类配体都提供了巨大的机会来影响催化领域，就像叔膦、n -杂环碳和单阴离子钳形配体在过去几十年里所做的那样。这些配体开辟了新的未开发的实验空间，同时提供了对金属的立体力学和电子学的卓越控制。在该计划的过程中，钴的配位化学将被广泛研究，以扩大这种地球上丰富的金属在催化转化中的应用，催化转化通常由更昂贵和稀有的贵金属主导。对这些定义良好的过渡金属配合物的研究将为包括水氧化在内的重要催化转化提供宝贵的基础知识和深刻的见解。

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.