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2005
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In the Laboratory
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Catalytic Oxygen Evolution by a Bioinorganic Model of the Photosystem II Oxygen-Evolving Complex
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Derrick L. Howard, Arthur D. Tinoco, Gary W. Brudvig, John S. Vrettos, and Bertha Connie Allen
Department of Chemistry, Yale University, New Haven, CT 06520-8107
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May 2005
Vol. 82 No. 5
p. 791
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| Abstract |
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Bioinorganic chemistry is a discipline that few undergraduates experience within a laboratory setting. This article details a series of experiments suitable for advanced undergraduates that will introduce them to the preparation and characterization of a bioinorganic model complex. Techniques and concepts emphasized include inorganic synthesis, UV&Ndash;visible spectroscopy, titrations, catalytic mechanisms, oxidation&Ndash;reduction reactions, and kinetics. The experiments are relevant to photosynthetic water oxidation, a process catalyzed by photosystem II (PSII) at an active site that contains a tetrameric μ-oxo-bridged manganese (Mn4) cluster. Bioinorganic models of the Mn4 cluster are invaluable in understanding the mechanism of water oxidation by PSII and possibly in developing artificial water-oxidation catalysts. In this laboratory, students explore the chemistry of a dimeric μ-oxo-bridged manganese complex that is a functional model for the Mn4 cluster. They synthesize the complex [(terpy)(H2O)MnIII(O)2MnIV(OH2)(terpy)]3- (terpy = 2,2':6',2"-terpyridine) and characterize the oxidation of terpy by one-electron using UVŠvisible spectroscopy. The terpy complex catalytically oxidizes H2O to O2 when peroxymonosulfate (oxone, HSO5-) is used as the primary oxidant. Students will measure the rate of O2 production and calculate the deuterium kinetic isotope effect when D2O is used in place of H2O as a substrate.
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| Supplement |
Detailed instructions for the students are available.
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 Contents |
JCE2005p0791W.doc (Microsoft Word)
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| Download |
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| More Information |
Citation |
Howard, Derrick L.; Tinoco, Arthur D.; Brudvig, Gary W.; Vrettos, John S.; Allen, Bertha Connie. J. Chem. Educ. 2005 82 791.
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Keywords |
Bioinorganic Chemistry; Inorganic Synthesis; Isotopes; Kinetics; Laboratory Instruction; Plant Chemistry; Redox Reactions
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History |
Created:
Last Updated: |
March 28, 2005
April 18, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2005
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May
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