- Professor, University of Notre Dame
- Associate Professor, University of Notre Dame
- Assistant Professor, University of Notre Dame
- Postdoctoral Fellow, California Institute of Technology
- Ph.D. in Inorganic Chemistry, University of Washington
- B.S. in Chemistry, B.S. in Humanities and Science, Massachusetts Institute of Technology
- Fellow of the American Chemical Society
- Edmund P. Joyce, CSC Award for Excellence in Undergraduate Teaching
- Shilts/Leonard award for outstanding teaching in the College of Science
- 2003, 2006
- John Kaneb Award for undergraduate teaching
- University of Notre Dame Presidential Award
- Thomas P. Madden Award for outstanding teaching in the first-year program
- NSF Career Award
- Dupont Young Professor Award
- Camille and Henry Dreyfus Foundation New Faculty Award
Developing Catalysis for Energy and the Environment
Enhancing our understanding of the mechanisms of chemical reactions is critical to improve processes that interconvert between chemical and electrical energy or to make chemical products in a selective and environmentally benign way. The Brown group is addressing this general problem by making new inorganic or organometallic complexes with the aim of achieving reactivity through novel mechanisms.
Traditionally, oxidation-reduction reactions mediated by metal-containing compounds involve changes in both the oxidation state and bonding that directly involve those metal centers. We are exploring an alternative mode of redox reactivity, what we term "nonclassical" redox reactions, where bond-making or bond-breaking events occur at a metal center but oxidations or reductions occur not at the metal center but at redox-active ligands attached to the metal. These processes generate novel species with unusual electronic structure, which may be capable of unusual reactivity. Furthermore, separating the locus of electron transfer from that of changes in bonding mimics the heterogeneous catalysis involved in fuel cells, suggesting that nonclassical homogeneous reactions may lead to conceptual insights or practical advances in systems for interconverting electrical and chemical energy.
In some cases, we have observed reactions where both the oxidation state changes and the bonding changes take place at the ligand rather than the metal. This has allowed us to observe reactions at coordinatively saturated or even encapsulated metal centers that would normally be considered poor choices as catalysts because of the unavailability of open sites at the metal. We are currently engaged in elucidating the effect of the metal-ligand bonding on this ligand-centered reactivity and using that information to design new catalysts with enhanced reactivity, selectivity, or durability.
- Marshall-Roth, T.; Brown, S.N. "Redox activity and π bonding in a tripodal seven-coordinate molybdenum(VI) tris(amidophenolate)." Dalton Trans. 2015, 44, 677-685.
- Shekar, S.; Brown, S.N. "Mechanism and Selectivity of Methyl and Phenyl Migrations in Hypervalent Silylated Iminoquinones." J. Org. Chem. 2014, 79, 12047-12055.
- Ranis, L.G.; Werellapatha, K.; Pietrini, N.J.; Bunker, B.A.; Brown, S.N. "Metal and Ligand Effects on Bonding in Group 6 Complexes of Redox-Active Amidodiphenoxides." Inorg. Chem. 2014, 53 (19), 10203-10216.
- Shekar, S.; Brown, S.N. "Mixed amidophenolate-catecholates of molybdenum (VI)." Dalton Trans. 2014, 43 (9), 3601-3611.
- Cipressi, J.; Brown, S.N. "Octahedral to trigonal prismatic distortion driven by subjacent orbital pi antibonding interactions and modulated by ligand redox noninnocence." Chem. Commun. 2014, 50 (59), 7956-7959.
- Randolph, A.H.; Seewald, N.J.; Rickert, K.; Brown, S.N. "Tris(3,5-di-tert-butylcatecholato)molybdenum(VI): Lewis Acidity and Nonclassical Oxygen Atom Transfer Reactions." Inorg. Chem. 2013, 52 (21), 12587-12598.