Silyl Pincer Transition Metal Complexes for Challenging Bond Activation and Catalysis

用于具有挑战性的键活化和催化的甲硅烷基钳过渡金属配合物

• 批准号: RGPIN-2019-04900
• 负责人: Turculet, Laura
• 金额: $ 3.5万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715225
• 关键词: Silyl; Pincer; Transition; Metal; Complexes

Transition metal catalysts play a key role in facilitating chemical processes that convert abundant raw material resources into value-added products (pharmaceuticals, flavors, fragrances, plastics, etc.) in an efficient, selective manner. Chemists have long focused on developing homogeneous catalysts that utilize scarce precious metals such as Pd, Pt, Rh, and Ru. Despite their efficacy, such catalysts are limited by the decreasing availability, and associated high cost, of the late 4d- and 5d-transition metals. Mining and processing of ores containing such metals is also highly energy intensive, generating large CO2 emissions. Faced with the pressing need to develop increasingly sustainable synthetic processes, interest in the reactivity of earth-abundant 3d-metals, such as Mn, Fe, Co, and Ni has grown significantly, with the goal of discovering new, effective catalysts to complement, and possibly supplant, precious metal-based technology. While nature has utilized 3d-transition metals almost exclusively for catalyzing chemical reactivity, harnessing this reactivity has proven challenging in the laboratory. In this regard, this proposal targets the development of new classes of broadly useful, sustainable 3d-metal catalysts for atom economical alkene and alkyne hydrofunctionalization, a class of widely used reactions for converting such feedstocks into consumer products. Our strategy builds upon our established success in developing highly reactive precious metal silyl pincer complexes. We seek to extend this ligation strategy to the 3d-metals, where we anticipate that silyl-metal cooperativity in element-hydrogen bond cleavage may provide reactivity advantages in hydrofunctionalization catalysis. While earth-abundant 3d-metal catalysts are highly desirable and will be our primary focus, the utility of precious metal complexes for targeted, challenging reactivity applications cannot yet be discounted. As such, a second area of investigation will target the development of new catalytic amination reactions facilitated by Ir silyl pincer species. Due to the prevalence of N-containing functional groups in pharmaceuticals and fine chemicals, significant interest exists in developing new atom-economical amination reactions, especially reactions that utilize ammonia - an inexpensive commodity chemical. Our group has established that Ir silyl pincer complexes can undergo challenging stoichiometric N-H bond oxidative addition reactions to cleave the N-H bonds of amines, including ammonia. In this proposal, we seek to capitalize on this novel reactivity in order to develop new catalytic processes for the functionalization of amines and ammonia, which would have wide applicability in chemical synthesis. The proposed studies will advance our understanding of transition metal mediated synthesis, will provide practical 3d-metal catalysts for uptake by end-users, and will provide world-class training for researchers in modern synthetic chemistry techniques.

过渡金属催化剂在促进将丰富的原材料资源转化为增值产品（药物，香料，香料，塑料等）的化学过程中发挥着关键作用。以一种有效的、有选择的方式。化学家长期以来一直致力于开发利用稀有贵金属如Pd，Pt，Rh和Ru的均相催化剂。尽管它们有效，但这种催化剂受到后4d-和5d-过渡金属的可用性降低和相关的高成本的限制。含有此类金属的矿石的开采和加工也是高度能源密集型的，会产生大量的二氧化碳排放。面对开发日益可持续的合成工艺的迫切需求，对地球上丰富的3d金属（如Mn，Fe，Co和Ni）的反应性的兴趣显着增长，目的是发现新的有效催化剂以补充并可能取代基于贵金属的技术。虽然自然界几乎只利用3d过渡金属催化化学反应，但在实验室中利用这种反应性已被证明具有挑战性。在这方面，该提案的目标是开发新类别的广泛有用的、可持续的3d-金属催化剂，用于原子经济的烯烃和炔烃加氢官能化，这是一类广泛使用的用于将这种原料转化为消费品的反应。我们的战略建立在我们在开发高反应性贵金属甲硅烷基钳形配合物方面取得的成功之上。我们试图将这种连接策略扩展到3d-金属，我们预计在元素-氢键断裂中的甲硅烷基-金属协同性可以在氢官能化催化中提供反应性优势。虽然地球上丰富的3d-金属催化剂是非常可取的，将是我们的主要重点，贵金属络合物的效用为目标，具有挑战性的反应性应用还不能被忽视。因此，第二个领域的调查将针对新的催化胺化反应的发展促进Ir甲硅烷基钳物种。由于含N官能团在药物和精细化学品中的普遍存在，对开发新的原子经济的胺化反应，特别是利用氨（一种廉价的商品化学品）的反应存在重大兴趣。我们的小组已经确定，铱甲硅烷基钳配合物可以进行具有挑战性的化学计量的N-H键氧化加成反应，裂解胺，包括氨的N-H键。在这个提议中，我们试图利用这种新的反应性，以开发新的催化方法，胺和氨的官能化，这将在化学合成中具有广泛的适用性。拟议的研究将推进我们对过渡金属介导合成的理解，将为最终用户提供实用的3d金属催化剂，并将为现代合成化学技术的研究人员提供世界一流的培训。