Electron Transfer Reactivity, Spectroscopy, and X-ray Crystallographic Analysis of Binuclear Manganese Complexes specifically: [MnIIIZnIIL](BF4)2 and [MnIIMnIIL]BF4 complexes

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Authors
Williams, Lori-Ann Y.
Issue Date
2013
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Thesis
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en_US
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Abstract
The occurrence of manganese atoms in biological electron transfer roles is well established, with prominent examples including bacterial catalases and the oxygen-evolving complex in photosynthesis in green plants. Manganese plays an important role in plant and cyanobacterial photosynthesis which is coupled to the oxidation of water by the photosystem II (PSII) tetranuclear Mn reaction center complex and in binuclear Mn active sites of catalases, which remove the overall levels of hydrogen peroxide produced by the process of metabolism in cells. The redox properties of simple manganese coordination complexes were explored using an organic macrobicyclic ligand. The cyclic voltammametry and differential pulse voltammetry of dimanganese(II) compounds showed two well separated one-electron oxidations in acetonitrile. The first wave was assigned to the oxidation of one manganese atom in solution. Solid-state MnIIMnIII and MnIIIMnII compounds were obtained by nitrosonium ion oxidation. All solid state manganese complexes were characterized using infrared and electronic absorption spectroscopy. X–ray crystallography determined a highly distorted octahedral coordination geometry (3 Mn ̶ O bonds and 3 Mn ̶ N bonds) about each metal for [MnIIIZnIIL](BF4)2 however, the Mn and Zn atoms could not be distinguished from one another and the structure was not completely resolved. Future research will include identifying the species responsible for the second electrochemical oxidation waves. We plan to explore redox reactivity toward small molecules such as hydrogen peroxide, dioxygen, and others.
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iv, 44 p.
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Kalamazoo College
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U.S. copyright laws protect this material. Commercial use or distribution of this material is not permitted without prior written permission of the copyright holder. All rights reserved.
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