With this CAREER award, the Chemical Synthesis Program will support the research of Professor Michael J. Zdilla of Temple University on the oxygen evolving complex (OEC) of photosystem II that is nature's solution to the most energetically taxing component of solar water splitting. This catalyst is a manganese-calcium-oxo cluster which undergoes structural rearrangements via a 5-stage catalytic cycle whereby it oxidizes water to oxygen, pumps protons across the thylakoid membrane, and harvests reducing equivalents for energy storage in sugars. In this area there is relatively extensive model chemistry of manganese clusters but the rearrangement chemistry and cluster flexibility, key components to the action of the OEC, are not well represented in the literature. Prof Zdilla's research program has two main foci: 1) the design and preparation of manganese clusters of enhanced flexibility via the avoidance of stabilizing chelating ligands, which lock cluster cores in place, and 2) study of reaction and rearrangement chemistry of these systems, especially in comparison to the well-established, more stable chelate clusters.
Global energy demand continues to grow exponentially while fossil fuel reserves continue to be depleted. To meet world energy demands, new solar energy technology must be developed. Nature's selection of a manganese cluster cofactor to achieve the difficult water oxidation reaction of photosynthesis suggests these molecules possess enormous transformative power for solar-powered water activation. The proposed work will pursue these goals in work that affords the opportunity for training of graduate and undergraduate students, and also provides minority training opportunities at Temple, one of the most ethnically and culturally diverse urban schools in the United States. The PI will continue his involvement in science outreach in the Philadelphia area through organizations like the Chemical Heritage Foundation, Nerd Nite Cafe, and the Philadelphia Science Festival. He will also pursue, along with the worldwide crystallographic community, the development of a much needed database of X-ray crystallographic educational resources, accessible to all teachers and students of crystallography, with the aim of providing extensive educational resources for this multi-field discipline.
