Metal-Metal Cooperativity Effects in Synthesis and Catalysis

合成和催化中的金属-金属协同效应开发新的催化剂，将简单而丰富的原材料转化为重要的化学品和药物，对于可持续和负责任的化学工业至关重要。高效和选择性的催化工艺降低了与化学合成相关的成本和废物。受天然含金属酶的启发，Michaelis博士正在开发含有两个不同金属中心的新催化剂。这两种金属协同工作，实现比单一金属更有效的催化作用。了解这一过程是如何发生的，使这种策略能够应用于广泛的催化反应。 Michaelis博士还积极参与招募和留住有前途的高中和本科学生，包括女性，进入科学，技术和工程（STEM）专业。这些努力使学生在职业生涯的早期阶段参与STEM领域的研究，服务和推广机会。这些活动包括高中和大学新生的暑期实习。过渡金属催化反应是现代有机合成的标志，在从基础合成研究到大规模制造的各个领域都发挥着关键作用。过渡金属催化中的传统配体设计试图通过改变有机支撑配体的电子和空间性质来控制反应机理、反应性和催化剂寿命。含有第二金属的配体代表了催化剂设计的概念上不同的方法，因为金属-金属协同性可以以独特的方式影响催化剂的反应性、机理和选择性。尽管在合成和表征双金属配合物方面做了大量的努力，但它们在有机合成中的应用仍然相对未被探索。 此外，目前还不清楚金属-金属相互作用在多大程度上可以实现机械上不同的反应途径。在化学部化学合成计划的资助下，Michaelis博士正在制定策略，以研究M-M相互作用对合成转化反应性和机制的影响。这些目标通过以下方式实现：（1）合成新的含钛配体，包括手性对映体纯配体，并研究用于烯烃和C-H活化反应的亲电Ti-M（M = Ni，Pd，Pt）杂环催化剂的组装，以及（2）合成（NHC）Ni-M2络合物（NHC = N-杂环卡宾）并研究M2在Ni催化的交叉偶联反应中的影响。Michaelis博士还积极参与STEM外展活动，包括高中和本科生的研究实习，并正在为化学和生物化学专业的新生制定指导计划。这个指导计划是确保本科生的多元化群体参与本科研究，推广，并在STEM领域的服务机会。

Metal-Metal Cooperativity Effects in Synthesis and CatalysisDeveloping new catalysts to convert simple and abundant raw materials into important chemicals and pharmaceuticals is essential for a sustainable and responsible chemical industry. Efficient and selective catalytic processes lower both the cost and waste associated with chemical synthesis. Inspired by natural metal-containing enzymes, Dr. Michaelis is developing new catalysts that contain two distinct metal centers. The two metals work cooperatively to achieve much more efficient catalysis than that of a single metal. Understanding how this process occurs is enabling the application of this strategy to a broad number of catalytic reactions. Dr. Michaelis is also actively involved in recruiting and retaining promising high school and undergraduate students, including women, into science, technology, and engineering (STEM) majors. These efforts are involving students in research, service, and outreach opportunities within the STEM field at an early stage of their career. The activities include summer internships at the high school and college freshman levels.Transition-metal catalyzed reactions represent a hallmark of modern organic synthesis and play a critical role in areas ranging from basic synthetic research to large scale manufacturing. Traditional ligand design in transition metal catalysis seeks to control reaction mechanism, reactivity, and catalyst lifetime by varying the electronic and steric properties of organic supporting ligands. Ligands that contain a second metal represent a conceptually distinct approach to catalyst design because metal-metal cooperativity can impact the reactivity, mechanism, and selectivity of catalysts in unique ways. Despite significant efforts to synthesize and characterize bimetallic complexes, their application to organic synthesis remains relatively unexplored. In addition, it remains unclear to what extent metal-metal interactions can enable mechanistically distinct reaction pathways. With funding support from the Chemical Synthesis Program of the Chemistry Division, Dr. Michaelis is developing strategies to investigate the impact of M-M interactions on reactivity and mechanism in synthetic transformations. These goals are being achieved by (1) synthesizing new titanium-containing ligands, including chiral enantiopure ligands, and investigating the assembly of electrophilic Ti-M (M = Ni, Pd, Pt) heterobimetallic catalysts for olefin and C-H activation reactions, and (2) Synthesizing (NHC)Ni-M2 complexes (NHC = N-heterocyclic carbene) and investigating the impact of M2 in Ni-catalyzed cross coupling reactions. Dr. Michaelis is also actively involved in STEM outreach activities, including high school and undergraduate research internships, and is developing a freshman mentoring program for chemistry and biochemistry majors. This mentoring program is ensuring that a diverse group of undergraduate students participate in undergraduate research, outreach, and service opportunities within the STEM field.