This award in the Division of Chemistry supports research by Professor Seth N. Brown at the University of Notre Dame to explore the activation of monometallic centers by nonclassical oxygenation reactions. The main strategy is based on using redox-active ligands that use small bite angles to encourage higher coordination numbers on complexes of molybdenum and tungsten. Ligands will include both known (catecholate, bis(iminophenoxide), amidobis(phenoxide)) and novel (hexadentate tris- (iminophenoxide), bis(hydroxyphenyl)triazole) designs. Interactions of molecular oxygen with complexes of the reduced ligands, as well as possible molecular oxygen generation from dioxo complexes of the oxidized ligands, will be studied mechanistically. The ability of the ligand-oxidized oxo complexes to deliver oxygen to substrates will also be analyzed to determine the geometric and electronic factors that encourage this reaction. Possible catalytic reactions that combine molecular oxygen activation with atom transfer to organic substrates, such as oxidative cleavage of alkenes (i.e., ozonolysis using molecular oxygen), will be explored.
This research explores ways to synthesize oxygen-containing organic molecules more efficiently. Activating molecular oxygen is a prime target for catalysis, with impacts in green chemical synthesis and renewable energy storage. It is a difficult target because the intermediate oxidation states of dioxygen (such as peroxide) are high in energy, placing an intrinsic roadblock on efficient reactions. The research will provide broad training of postdoctoral, graduate, and undergraduate students. Undergraduates (including members of underrepresented groups) will be recruited and encouraged to pursue research throughout their undergraduate careers. Graduate students and especially postdoctoral scholars will be encouraged to mentor undergraduates in collaboration with the PI in order to assist in their training and provide them with motivation to pursue careers in teaching and research.