The protonation state of trans axial water molecule switches: the reactivity of high-valent manganese-oxo porphyrin
| Autor: | Geneviève Pratviel, Joris Irvoas, Jérôme Trzcionka |
|---|---|
| Přispěvatelé: | Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées |
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
010405 organic chemistry
Ligand chemistry.chemical_element Protonation General Chemistry Manganese 010402 general chemistry Photochemistry 01 natural sciences Porphyrin Redox Catalysis 0104 chemical sciences Electron transfer chemistry.chemical_compound chemistry Materials Chemistry Molecule Reactivity (chemistry) [CHIM.COOR]Chemical Sciences/Coordination chemistry |
| Zdroj: | New Journal of Chemistry New Journal of Chemistry, Royal Society of Chemistry, 2013, 37 (11), pp.3581. ⟨10.1039/C3NJ01004J⟩ |
| ISSN: | 1144-0546 1369-9261 |
| Popis: | International audience; The cationic manganese porphyrin (Mn-TMPyP) was activated by an oxygen atom donor KHSO5 (oxone) to form a high-valent manganese-oxo species (MnV[double bond, length as m-dash]O) in aqueous buffer. The high-valent MnV[double bond, length as m-dash]O mediated oxidative damage of short double-stranded DNA models. The nature of the oxidation products (guanine oxidation DGh, 2Ih, imidazolone, and 2-deoxyribose oxidation, 2-deoxyribonolactone) and the mechanism of their formation varied with the pH of the reaction. Oxidation proceeded mainly through the electron transfer mechanism at pH 6 while oxygen atom transfer proved to be favored at pH 8. This was evidenced by different ratios of products arising from different mechanisms of oxidation as a function of pH but also by different mechanisms leading to the same oxidation product (DGh) as a function of pH. The reactivity shift of the active manganese-oxo species was attributed to the protonation state of the proximal water molecule as an axial ligand (trans to the oxo). A high-valent manganese-oxo in the oxo-hydroxo form (HO–MnV[double bond, length as m-dash]O) at higher pH undergoes oxygen atom transfer reactions while in the oxo-aqua form (H2O–MnV[double bond, length as m-dash]O) at lower pH it performs oxidation reactions by electron transfer. These data are an illustration of the influence of the “push” effect of the proximal ligand on the changing reactivity of high-valent metal-oxo species. They also give access to the pKa of the axially bound water molecule of manganese-oxo porphyrin. |
| Databáze: | OpenAIRE |
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