Metal-Metal Cooperativity Effects in Synthesis and Catalysis

Brigham Young University, Provo UT

Investigators

Abstract

Metal-Metal Cooperativity Effects in Synthesis and Catalysis Developing 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.