Understanding the Mechanism of Solar Water Oxidation in Natural and Artificial Water Oxidation Catalysts

K. V. Lakshmi
Rensselaer Polytechnic Institute
Online WebEx seminar
Wed, April 13, 2022 at 11:00 AM
The solar water-splitting protein complex, photosystem II (PSII), catalyzes one of the most energetically demanding reactions in Nature by using light energy to drive water oxidation. The four-electron water oxidation reaction occurs at the tetra-nuclear manganese-calcium-oxo (Mn4Ca-oxo) cluster that is present in the oxygen-evolving complex of PSII. The electronic and geometric structure of the Mn4Ca-oxo cluster, which is exquisitely tuned by smart protein matrix effects, is central to the water-oxidation chemistry of PSII. However, the mechanism of water oxidation at the Mn4Ca-oxo cluster is not well understood because of the inability of conventional methods to directly probe the reaction intermediates. We are developing high resolution two-dimensional (2D) hyperfine sublevel correlation spectroscopy methods that provide direct ‘snapshots’ of the photochemical water oxidation intermediates of the Mn4Caoxo cluster of PSII. Moreover, we are using the design principles of the oxygen-evolving complex of PSII to synthesize bio-inspired catalysts that mimic the electronic and geometric structure of the Mn4Ca-oxo cluster. I will describe ongoing efforts in our laboratory to understand the mechanism of water oxidation in both natural and bio-inspired artificial systems.
K V Lakshmi
K. V. Lakshmi is a Professor in the Department of Chemistry and Chemical Biology and Director of the Baruch ’60 Center for Biochemical Solar Energy Research at Rensselaer. She is trained in the development and application of advanced biophysical spectroscopy at Brandeis University, MIT, and Yale University. She is recognized for her research on the development of state-of-the-art multi-frequency multidimensional pulsed EPR spectroscopy, solids NMR spectroscopy and electron-nuclear spectroscopy methods. She applies her advanced training in magnetic resonance spectroscopy, molecular genetics, biochemistry, inorganic chemistry, computational chemistry and in situ observation of light-driven intermediates to address the molecular mechanisms of solar energy conversion in natural and artificial systems. She is the recipient of several awards for her research including the Bioenergetics Award by the Biophysical Society and Therese Cotton Memorial Award by the Gordon Research Foundation.