Publication
768
J. Inorg. Biochem., 146, 69-76, 2015
DOI:10.1016/j.jinorgbio.2015.02.012
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A new mononuclear manganese(III) complex of an unsymmetrical hexadentate N3O3 ligand exhibiting superoxide dismutase and catalase-like activity: synthesis, characterization, properties and kinetics studies |
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Gabriela N. Ledesma, Hélène Eury, Elodie Anxolabéhère-Mallart, Christelle Hureau, and Sandra R. Signorella
IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK), Rosario, Argentina
Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
Université de Toulouse; UPS, INPT, LCC, F-31077 Toulouse, France
Laboratoire d'Electrochimie Moléculaire UMR CNRS-P7 7591 Université Paris Diderot-Paris, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
A mononuclear MnIII complex MnL·4H2O (H3L = 1-[N-(2-pyridylmethyl),N-(2-hydroxybenzyl)amino]-3-[N′-(2-hydroxybenzyl),N′-(4-methylbenzyl)amino]propan-2-ol) has been prepared and characterized. This complex catalyzes the dismutation of superoxide efficiently, with catalytic rate constant kcat = 1.7 × 106 M− 1 s− 1 and IC50 1.26 μM, obtained through the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, in aqueous solution of pH 7.8. MnL is also able to disproportionate more than 300 equivalents of H2O2 in CH3CN, with initial rate of H2O2 decomposition given by ri = kcat [MnL]2 [H2O2] and kcat = 1.32(2) mM− 2 min− 1. The accessibility of the MnIV state (Ep = 0.53 V vs. saturated calomel electrode), suggests MnL employs a high-valent catalytic cycle to decompose O2radical dot− and H2O2. |
