Representative Research Areas

Redox-Active and Dinucleating Ligands in Homogeneous Catalysts for Carbon Dioxide Reduction

Carbon dioxide is a greenhouse gas, but also represents a readily accessible C1 building block for energy applications as well as value-added chemical feedstocks. However, CO2 is relatively inert and very negative voltages or strong chemical reductants are common for its conversion. An additional challenge lies in achieving this reaction in water where aqueous protons are utilized selectively for CO2 reduction rather than hydrogen generation. Our strategy for CO2-to-fuel conversion involves the design of homogeneous catalysts with redox-active and/or dinucleating ligands, which enable access to multiple reducing equivalents at modest potentials and cooperative modes of CO2 activation, respectively.

Robust, High-Spin Iron-Oxo Catalysts for Oxidizing Water and Hydrocarbons

High-valent iron-oxo species are potent oxidants in chemistry and biology for a variety of reactions, including oxidation of water and hydrocarbons. In this context, the vast majority of synthetic Fe(IV)-oxo systems possess low-spin ground states produced by harsh oxidants (Ce(IV), iodosobenzene, etc), whereas natural systems generate more reactive high-spin Fe(IV)-oxos with mild oxidants (O2, H2O2). Indeed, only seven synthetic high-spin Fe(IV)-oxo complexes have been reported, all of which suffer from poor stability and/or sluggish reactivity. We aim to develop new Fe-oxo catalysts with oxidatively-rugged ligands that enforce low-coordinate geometries favoring high-spin electronic states to overcome these limitations.

Bioinspired Chemistry on Surfaces: Controlling the Second-Coordination Sphere

Nature tightly regulates the environment around metalloenzyme active sites to achieve catalysis with high efficiency and selectivity. This environment, comprised of specific noncovalent interactions such as hydrogen bonding, is referred to as the second-coordination sphere and plays a key role in orchestrating reactivity at the first-coordination sphere. We seek to mimic this concept on electrode surfaces to develop modular and scalable catalytic systems to manage proton inventories, stabilize intermediates, and direct reaction pathways.