Chlorine K-Edge X-ray Absorption Spectroscopy as a Probe of Chlorine-Manganese Bonding: Model Systems with Relevance to the Oxygen Evolving Complex in Photosystem II

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• 作者：Annette Rompel ; Joy C. Andrews ; Roehl M. Cinco ; Michael W. Wemple ; George Christou ; Neil A. Law ; Vincent L. Pecoraro ; Kenneth Sauer ; Vittal K. Yachandra ; and Melvin P. Klein
• 刊名：Journal of the American Chemical Society
• 出版年：1997
• 出版时间：May 14, 1997
• 年：1997
• 卷：119
• 期：19
• 页码：4465 - 4470
• 全文大小：174K
• 年卷期：v.119,no.19(May 14, 1997)
• ISSN：1520-5126

文摘

For a series of Mn-Cl coordination complexes thechlorine K-edge X-ray absorption spectra (XAS) havebeen measured to probe chloride-manganese bonding. Results showthat in a series of mononuclear (single Mn)compounds with Cl covalently bound to Mn, the intensity of the pre-edgefeature increases in the order Mn^II <Mn^III< Mn^IV. For a series of distorted cubane complexes(containing 4 Mn) with bridging and terminal Cl ligands,threepre-edge features are seen. The pre-edge peak at lowest energyincreases in intensity as more terminal Cl are includedin the compounds. The origin of these features in the edge spectrais described in terms of the symmetry and ligandfield splittings expected for the Mn complexes. The Mn modelsystems studied here have potential application tothe oxygen evolving complex (OEC) in Photosystem II (PSII), wheredirect structural evidence for a halide bindingsite on the Mn cluster in one or more S-states of the Kok cycle wouldbe informative.