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

GABRIELA N. LEDESMA; HELENE EURY; ELODIE ANXOLABEHERE-MALLART; CHRISTELLE HUREAU; SANDRA R. SIGNORELLA

JOURNAL OF INORGANIC BIOCHEMISTRY

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2015 vol. 146 p. 69 - 76

0162-0134

A mononuclear MnIII complex MnL3H2O (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 x 106 M-1 s-1 and IC50 1.26 uM, 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 SCE), suggests MnL employs a high-valent catalytic cycle to decompose O2 and H2O2.