Note: ROSEI is cohosting this seminar with the Department of Chemistry.

Title: Moving Hydrogen and Oxygen: From Bioinspired Coordination Complexes to Nanoscale Materials

Abstract: Metal ions are ubiquitous in biology & materials and aid in facilitating many chemical transformations. For instance, iron-oxido and -hyrdoxido species are proposed to be key intermediates in oxidative processes catalyzed by non-heme iron proteins. To investigate the properties of both mono- and bimetallic cores, I have developed a symmetric multifunctional tripodal ligand framework, which can stabilize high-valent metal centers, form hydrogen-bounding networks, facilitate intramolecular proton transfer, and provide an auxiliary binding-site for a second metal ion. This presentation will describe my efforts to access high-valent diiron-oxido and -hydroxido species by a variety of synthetic routes.

Similarly, movement of protons, electrons, and oxygen atoms at the material-solution interface are elementary steps in heterogeneous catalysis. My approach is to quantify the thermodynamic properties of iridium oxide nanoparticles (IrOx NPs) using stoichiometric chemical reactions. By treating the NPs with chemical reactants that promote e-transfer or the coupling of n H+/ne- movement and monitoring spectroscopically, I have determined the PCET thermochemistry, in other measurements to oxygen-atom transfer reactivity. My findings suggest the kinetic rate of these reactions are dependent on the average oxidation states and surface coverage of the IrOx NPs, which are increasingly recognized as important considerations in surface catalysis.