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Mechanistic information on $Cu^{II}$ metalation and transmetalation of chlorophylls


Mechanistic information on $Cu^{II}$ metalation and transmetalation of chlorophylls

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dc.contributor.author Orzeł, Łukasz [SAP11019169] pl
dc.contributor.author van Eldik, Rudi [SAP14007947] pl
dc.contributor.author Fiedor, Leszek [SAP11012795] pl
dc.contributor.author Stochel, Grażyna [SAP11011061] pl
dc.date.accessioned 2015-09-16T12:33:26Z
dc.date.available 2015-09-16T12:33:26Z
dc.date.issued 2009 pl
dc.identifier.issn 1434-1948 pl
dc.identifier.uri http://ruj.uj.edu.pl/xmlui/handle/item/15696
dc.language eng pl
dc.title Mechanistic information on $Cu^{II}$ metalation and transmetalation of chlorophylls pl
dc.type JournalArticle pl
dc.description.physical 2393-2406 pl
dc.abstract.en Chlorophyll a and pheophytin a have been treated with various metal salts in solution. As a result, metallo derivatives of photosynthetic pigments were formed, or the chlorine ring was oxidized. These studies showed that both effects can be caused by CuII ions depending on the redox potential of its complexes formed in specific media. In this report the results of studies on metal insertion and exchange reactions are presented. According to the common use of the “acetate method” in the synthesis of metallotetrapyrroles, and the fact that acetates coordinated to CuII ions protect chlorophylls from oxidative degradation, CuII acetate monohydrate was selected as main reagent. The metalation and transmetalation processes were investigated with spectroscopic (UV/Vis absorption and emission) and kinetic (conventional and high-pressure) techniques. It turned out that differences in solvent properties can significantly affect not only the rates (metalation), but also the course (transmetalation) of the reaction. The most pronounced effect was found for the transmetalation reaction in acetonitrile, which was terminated at the very initial stage. As shown elsewhere, some special agents/factors, such as excess of acetate, are required to facilitate the dissociation of Mg2+ and to push the reaction forward towards formation of the CuII derivative of chlorophyll. The mechanisms of two other reactions are proposed on the basis of the determined activation parameters, which correspond to the general mechanisms for metalation and transmetalation of tetrapyrroles with sitting-atop and bimetallic intermediates, respectively. The bimetallic complex of chlorophyll in methanol is probably the most stable complex of this type observed ever. It confirms that spontaneous exchange of Mg2+ by CuII occurring in plants must result from specific conditions and/or involve contribution from other components of the photosystem. pl
dc.description.volume 2009 pl
dc.description.number 16 pl
dc.identifier.doi 10.1002/ejic.200800662 pl
dc.identifier.eissn 1099-0682 pl
dc.title.journal European Journal of Inorganic Chemistry pl
dc.language.container eng pl
dc.affiliation Wydział Chemii : Zakład Chemii Nieorganicznej pl
dc.affiliation Wydział Biochemii, Biofizyki i Biotechnologii : Zakład Fizjologii i Biochemii Roślin pl
dc.subtype Article pl

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