CAS: Four-Coordinate Iron- and Cobalt-Carbene Complexes for Carbene-Transfer Catalysis

CAS：用于卡宾转移催化的四配位铁和钴卡宾配合物

• 批准号: 2154892
• 负责人: Carsten Milsmann
• 金额: $ 44.03万
• 依托单位: West Virginia University Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154892&HistoricalAwards=false
• 关键词: CAS; Four; Coordinate; Iron; Cobalt

With the support of the Chemical Catalysis program in the Division of Chemistry, Carsten Milsmann of West Virginia University will study transition metal catalysts based earth-abundant metals, specifically iron and cobalt. The construction of complex organic molecules is an important target in the development of novel pharmaceuticals, functional materials, and consumer products. The elaboration of building blocks such as olefins, aromatics, and saturated hydrocarbons into more complex structures can be achieved by chemical reactions involving carbene fragments, which typically require metal catalysts to proceed efficiently. The best catalyst systems available currently rely heavily on rare and precious metals, which increases the cost of the resulting products and presents sustainability challenges due to limited resource availability. This research aims to develop design principles for earth-abundant metal complexes that can replace precious metals in carbene transfer catalysis. The development of iron- and cobalt-catalyzed processes in particular has the potential to improve fine chemical production in the United States. Dr. Milsmann and his students will actively participate in community outreach involving the development and presentation of chemistry demonstrations at the K-12 level, and will develop new hands-on experiments for middle and high school students.With the support of the Chemical Catalysis program in the Division of Chemistry,Carsten Milsmann of West Virginia University will study the electronic structures of four-coordinate iron- and cobalt-carbene complexes and their resulting reactivities as competent intermediates in carbene transfer catalysis. Of particular interest are complexes with square-planar or cis-divacant octahedral geometries that possess open coordination sites adjacent to the carbenoid ligand. The first aim of these studies is to establish how changes in the molecular structure and coordination geometry influence the electronic structures of the resulting complexes and their reactive metal carbenoid fragments. The second aim seeks to connect differences in electronic structure to changes in reactivity by studying catalytically competent, isolable iron- and cobalt-carbene complexes. A key hypothesis of the proposed research is that open coordination sites in square-planar carbene complexes will allow unprecedented control over the regioselectivity of carbene transfer using directing groups on the substrates. Finally, the third aim is to investigate the potential of four-coordinate iron carbenes to engage in [2+2] cycloaddition chemistry, which is a key step toward iron catalyst-mediated olefin metathesis. The proposed complexes possess coordinatively unsaturated metal centers, potentially opening up new opportunities for the control of reactivity compared to previously reported iron-carbene complexes. These studies will directly probe recent computational predictions that have identified iron-carbene complexes with pincer-type ligands as promising candidates for olefin metathesis catalysis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学催化项目的支持下，西弗吉尼亚大学的卡斯滕·米尔斯曼将研究基于地球上丰富的金属，特别是铁和钴的过渡金属催化剂。复杂有机分子的构建是开发新型药物、功能材料和消费品的重要目标。将烯烃、芳烃和饱和碳氢化合物等组成部分精制成更复杂的结构，可以通过涉及碳碎片的化学反应来实现，这通常需要金属催化剂才能有效地进行。目前最好的催化剂系统严重依赖于稀有和贵重金属，这增加了产品的成本，并且由于资源有限，对可持续性提出了挑战。本研究的目的是开发地球丰富的金属配合物的设计原则，以取代在碳转移催化中的贵金属。特别是铁和钴催化工艺的发展有可能改善美国的精细化学品生产。米尔斯曼博士和他的学生将积极参与社区外展活动，包括开发和展示K-12级别的化学演示，并将为初中和高中学生开发新的动手实验。在化学系化学催化项目的支持下，西弗吉尼亚大学的Carsten Milsmann将研究四配位铁和钴碳配合物的电子结构，以及它们作为碳转移催化的活性中间体的反应活性。特别令人感兴趣的是具有方形平面或顺距八面体几何形状的配合物，它们具有与类碳配体相邻的开放配位位点。这些研究的第一个目的是确定分子结构和配位几何的变化如何影响所得到的配合物及其活性金属类碳碎片的电子结构。第二个目标是通过研究催化能力强、可分离的铁和钴碳配合物，将电子结构的差异与反应性的变化联系起来。提出的研究的一个关键假设是，方形平面卡宾配合物中的开放配位位点将允许使用底物上的定向基团对卡宾转移的区域选择性进行前所未有的控制。最后，第三个目的是研究四配位铁羰基参与[2+2]环加成化学的潜力，这是铁催化剂介导的烯烃复分解的关键步骤。所提出的配合物具有配位不饱和金属中心，与先前报道的铁碳配合物相比，可能为控制反应性开辟新的机会。这些研究将直接探索最近的计算预测，这些预测已经确定了具有钳型配体的铁-碳配合物是烯烃复分解催化的有希望的候选者。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。