Liu G, Filipovic M, Heinemann FW, Ivanovic-Burmazovic I (2007)
Publication Type: Journal article, Original article
Publication year: 2007
Original Authors: Liu G., Filipović M., Heinemann F., Ivanović-Burmazović I.
Publisher: American Chemical Society
Book Volume: 46
Pages Range: 8825-8835
Journal Issue: 21
DOI: 10.1021/ic7012039
The reactions of seven-coordinate [Fe(dapsox)(H O)]Cl0·HO (1), [Fe (Hdapsox)(HO)](NO )·HO (2), and [Mn(H dapsox)(CHOH)(HO)](ClO) (HO) (3) complexes of the acyclic and rigid pentadentate Hdapsox ligand [Hdapsox = 2,6- diacetylpyridinebis(semioxamazide)] with superoxide have been studied spectrophotometrically, electrochemically, and by a submillisecond mixing UV/vis stopped-flow in dimethyl sulfoxide (DMSO). The same studies were performed on the seven-coordinate [Mn(Me[15]pyridinaneN )(HO)]Cl·HO (4) complex with the flexible macrocyclic Me[15]pyridinaneN ligand (Me[15]pyridinaneN = trans-2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),14, 16-triene), which belongs to the class of proven superoxide dismutase (SOD) mimetics. The X-ray crystal structures of 2-4 were determined. All complexes possess pentagonal-bipyramidal geometry with the pentadentate ligand in the equatorial plane and solvent molecules in the axial positions. The stopped-flow experiments in DMSO (0.06% of water) reveal that all four metal complexes catalyze the fast disproportionation of superoxide under the applied experimental conditions, and the catalytic rate constants are found to be (3.7 ± 0.5) × 10, (3.9 ± 0.5) × 10, (1.2 ± 0.3) × 10, and (5.3 ± 0.8) × 10 M s for 1-4, respectively. The cytochrome c McCord-Fridovich (McCF) assay in an aqueous solution at pH = 7.8 resulted in the IC values (and corresponding k constants) for 3 and 4, 0.013 ± 0.001 μM (1.9 ± 0.2 × 10 M s) and 0.024 ± 0.001 μM (1.1 ± 0.3 × 10 M s), respectively. IC values from a nitroblue tetrazolium assay are found to be 6.45 ± 0.02 and 1.36 ± 0.03 μM for 1 and 4, respectively. The data have been compared with those obtained by direct stopped-flow measurements and discussed in terms of the side reactions that occur under the conditions of indirect assays. © 2007 American Chemical Society.
APA:
Liu, G., Filipovic, M., Heinemann, F.W., & Ivanovic-Burmazovic, I. (2007). Seven-coordinate iron and manganese complexes with acyclic and rigid pentadentate chelates and their superoxide dismutase activity. Inorganic Chemistry, 46(21), 8825-8835. https://doi.org/10.1021/ic7012039
MLA:
Liu, Gaofeng, et al. "Seven-coordinate iron and manganese complexes with acyclic and rigid pentadentate chelates and their superoxide dismutase activity." Inorganic Chemistry 46.21 (2007): 8825-8835.
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