Prof. Andy Borovik
Title: Molecular Complexity: controlling proton/electron transfer and spin states within mono- and binuclear Fe-oxido systems
Bio:
A. S. Borovik was raised in Chicago and received his B.S. degree in Chemistry with Honors from Humboldt State University. As an undergraduate student he did research at Oregon State University as an NSF Summer Fellow and at Woods Hole Oceanographic Institution as a WHOI Fellow. Both research experiences involved using nuclear chemistry to trace metal ions in the environment. He obtained his Ph.D. in Chemistry at the University of North Carolina-Chapel Hill under Tom Sorrell where he developed photophysical models for the active site of copper proteins. As an NIH postdoctoral fellow with Larry Que at the University of Minnesota, he designed synthetic complexes that replicated the properties of dinuclear iron centers in proteins. Upon completion of his postdoctoral fellowship, Professor Borovik joined the faculty at Ithaca College where he taught chemistry and mentored 6 undergraduate research students for two years. He then moved to the University of California-Berkeley as a postdoctoral associate with Ken Raymond, working on stereonostic coordination chemistry. From there, he joined the Chemistry Department at Kansas State University where he began a broad program on the effects of the secondary coordination sphere on metal ions. After 3 years, he moved his research group to the University of Kansas, continuing research on the development of metal complexes and hybrid porous solids with unique structural and functional properties. In 2006, Professor Borovik and his research group moved to the University of California-Irvine, expanding his approach to include designing artificial metalloproteins. Professor Borovik has won several teaching and research awards that include a 2017 MERIT Award from the NIH, the 2018 National Cotton Award in Synthetic Inorganic Chemistry from the American Chemical Society, and the 2019 Tolman Award from the Southern California Section of the American Chemical Society. He is currently a UCI Distinguished Professor and was the 2022 Chair of the Division of Inorganic Chemistry of the American Chemical Society.
Abstract:
Metalloproteins perform functions not yet achieved in abiotic systems. One reason for this lack of function is the inability of control of the microenvironments about the metal centers. Microenvironments are defined as the volume of space proximal to the metal centers that encompass the secondary coordinate spheres. Results from structural biology point to non-covalent interactions within microenvironments as instrumental in regulating function. Therefore, the function and dysfunction of metalloproteins can be understood within the context of changes within their microenvironments. We are developing systems that allows for the confinement of metal ions within hosts to regulate their properties. One of our approaches revolves around the development of new ligand frameworks that are multi-functional in that they can bind a variety of different metal ions and simultaneously control both the primary and secondary coordination spheres. An example is the phosphinic amido ligand that can form an Fe(II) complex that can be converted into a high spin Fe(IV)-oxido complex. In addition, it can be used as a synthon to assemble discrete bimetallic complexes. This presentation will describe how local environments around Fe(IV)-oxido unit have a major impact on the electronic structure. Also discussed will be our efforts to assembled discrete FeFe and FeCo bimetallic complexes with oxido and hydroxido bridged cores and we demonstrate that these systems can control proton and electron transfer processes and spin states. For the FeFe system we achieved control of proton and electron transfer processes over four oxidation states from Fe(II)Fe(II) to Fe(IV)Fe(III). For FeCo system, we demonstrate that control of paramagnetism of the complex is mediated by a single proton that resides on bridging oxygen atom – when it is an oxido ligand, the Co(III) site become high spin, representing a unique example of a high spin, hexacoordinate Co(III) center that is stable in solution at temperatures ranging from 4-300 K.
Keywords: C-H Bond Acidities, Metal-Oxido Species, Proton-Couple Electron Transfer, Imbalanced Transition States
Faculty Host: Prof. Thomas Brunold