Electrocatalytic reduction of nitric oxide by water-soluble manganese porphyrins

Yu, C. H.; Su, Yu

doi:10.1016/0022-0728(93)03073-x

Cited by 53 publications

(29 citation statements)

References 26 publications

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“…The corresponding half-wave potentials, E1 ⁄2 were calculated as the average of cathodic and anodic peaks and are given as V versus NHE (Table V) along with the corresponding currents in A. The redox potential of the para isomer agrees well with literature data (37), whereas the E1 ⁄2 of the ortho isomer is ϳ40 mV more positive than reported (21). Cyclic voltammetry was also performed in the presence of RNA and DNA.…”

Section: Table I Optical Characteristics Of the Ortho Meta And Parasupporting

confidence: 74%

“…The same was found for other porphyrins in which meso phenyl groups have different ortho substituents, as well as when meso groups are ortho pyridyls, such as 5,10,15,20-tetrakis-(N-methylpyridinium-2-yl) (H 2 TM-2-PyP 4ϩ ) and its zinc complex, ZnTMP-2-PyP 4ϩ (15)(16)(17)(18)(19). Such a profound impact on the properties of the ortho isomers, known as the ortho effect, is due to the combined effect of inductive, resonance, and steric factors (20,21). For this reason, we explored the ortho isomer of manganese(III) 5,10,15,20-tetrakis(N-methylpyridyl)porphyrin (MnTMPyP 5ϩ ) and expected more favorable electrostatic facilitation due to the positively charged pocket formed in both the ␣␣␣␣ and ␣␣␣␤ atropoisomers (22,23).…”

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confidence: 99%

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The Ortho Effect Makes Manganese(III)Meso-Tetrakis(N-Methylpyridinium-2-yl)Porphyrin a Powerful and Potentially Useful Superoxide Dismutase Mimic

Batinić‐Haberle¹,

Benov²,

Spasojević³

et al. 1998

Journal of Biological Chemistry

256

300

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The ortho, meta, and para isomers of manganese(III) 5,10,15,20-tetrakis(N-methylpyridyl)porphyrin, MnTM-2-PyP 5؉ , MnTM-3-PyP 5؉, and MnTM-4-PyP 5؉ , respectively, were analyzed in terms of their superoxide dismutase (SOD) activity in vitro and in vivo. The impact of their interaction with DNA and RNA on the SOD activity in vivo and in vitro has also been analyzed. Differences in their behavior are due to the combined steric and electrostatic factors. In vitro catalytic activities are closely related to their redox potentials. The half-wave potentials (E1 ⁄2 ) are ؉0.220 mV, ؉0.052 mV, and ؉0.060 V versus normal hydrogen electrode, whereas the rates of dismutation (k cat ) are 6.0 ؋ 10 7 , 4.1 ؋ 10 6 , and 3.8 ؋ 10 6 M ؊1 s ؊1 for the ortho, meta, and para isomers, respectively. However, the in vitro activity is not a sufficient predictor of in vivo efficacy. The ortho and meta isomers, although of significantly different in vitro SOD activities, have fairly close in vivo SOD efficacy due to their similarly weak interactions with DNA. In contrast, due to a higher degree of interaction with DNA, the para isomer inhibited growth of SOD-deficient Escherichia coli.Due to their high stability and chemical versatility, manganese porphyrins are a promising group of compounds for development as SOD 1 mimics. Introducing ␤-electron-withdrawing substituents and modifying meso substituents of water soluble porphyrins can have a major impact on the redox and electrostatic properties of manganese porphyrins (1-7). Such substitution allows the redox potential to approach the potential of SOD itself, E1 ⁄2 ϳ ϩ0.26 V (8). This is approximately midway between the redox potentials of the two half-reactions of the dismutation process (9, 10). While maintaining the redox potential at a value close to that of SOD, it is important to also ensure electrostatic facilitation. We have already shown that ␤-bromination (11, 12) of the manganese(III) 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin (13) and of manganese(III) 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin increases their SOD-like activities (13).2 However, the large positive redox potential of the former, E1 ⁄2 ϭ ϩ0.480 mV versus NHE, (13) stabilizes manganese in its 2ϩ state and diminishes stability, and the latter compound had only modest activity, probably due to lack of electrostatic facilitation (13).It has been shown that ortho substitution on the meso phenyl ring exhibits an ortho effect that is as strong as if the same substituent were placed directly on the meso position (14). Thus, meso-tetrakis(2-methylphenyl)porphyrin behaves similar to the meso tetramethylporphyrin (14). The same was found for other porphyrins in which meso phenyl groups have different ortho substituents, as well as when meso groups are ortho pyridyls, such as 5,10,15,20-tetrakis-(N-methylpyridinium-2-yl) (H 2 TM-2-PyP 4ϩ ) and its zinc complex, ZnTMP-2-PyP 4ϩ (15)(16)(17)(18)(19). Such a profound impact on the properties of the ortho isomers, known as the ortho effect, is due to the combi...

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Section: Table I Optical Characteristics Of the Ortho Meta And Parasupporting

confidence: 74%

mentioning

confidence: 99%

The Ortho Effect Makes Manganese(III)Meso-Tetrakis(N-Methylpyridinium-2-yl)Porphyrin a Powerful and Potentially Useful Superoxide Dismutase Mimic

Batinić‐Haberle¹,

Benov²,

Spasojević³

et al. 1998

Journal of Biological Chemistry

256

300

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“…Porphyrins have been used extensively for the electrochemical reduction of nitrite [26][27][28][29] but an unwanted side product of hydroxylamine is formed. Redox polymer films have also been utilised in nitrite reduction [30], but the polymer film formed was found to swell when immersed in electrolyte solution.…”

Section: Cyclic Voltammetry Of Multilayer System In the Presence Of Smentioning

confidence: 99%

Assembly, electrochemical characterisation and electrocatalytic ability of multilayer films based on [Fe(bpy)3]2+, and the Dawson heteropolyanion, [P2W18O62]6−

Fay¹,

Dempsey²,

McCormac³

2005

Journal of Electroanalytical Chemistry

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Abstractimmobilise up to thirty monolayers, with the system exhibiting well behaved redox behaviour. The stability of the assembly towards redox switching was investigated, with it being found be extremely stable once the outer layer is anionic in nature. The 2 immobilised film was also tested for electrocatalytic activity for the reduction of nitrite, hydrogen peroxide and bromate, and was shown to be an efficient electrocatalyst.

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“…The electroreduction of nitrite at most electrode surfaces requires a large overpotential, but it has been previously shown to be catalyzed by metallated porphyrins [1][2][3][4]. Being catalytic analogues to porphyrins, monosubstituted polyoxometalates (POMs) have the additional advantage of thermal stability, robustness and inertness towards oxidizing environments.…”

Section: Introductionmentioning

confidence: 99%

Electrocatalysis by crown-type polyoxometalates multi-substituted by transition metal ions; Comparative study

Naseer

Mal

Kortz

et al. 2015

Electrochimica Acta

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The difference in electrochemical properties of three crown-type polyoxometalates multisubstituted by Fe 3+ , Ni 2+ or Co 2+ ions and their precursor has been rationalized with respect to their electrocatalytic performances studied in solution and in the immobilized state within the layer-by-layer film formed with a positively charged pentaerythritol-based Ru(II)-metallodendrimer. The film assembly was monitored with electrochemical methods and characterized by surface analysis techniques. An influence of the terminal layer on the electrode reaction and on film porosity has been observed. The electrocatalytic performance of the compounds on nitrite reduction was assessed in solution and in the immobilized state.

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Electrocatalytic reduction of nitric oxide by water-soluble manganese porphyrins

Cited by 53 publications

References 26 publications

The Ortho Effect Makes Manganese(III)Meso-Tetrakis(N-Methylpyridinium-2-yl)Porphyrin a Powerful and Potentially Useful Superoxide Dismutase Mimic

The Ortho Effect Makes Manganese(III)Meso-Tetrakis(N-Methylpyridinium-2-yl)Porphyrin a Powerful and Potentially Useful Superoxide Dismutase Mimic

Assembly, electrochemical characterisation and electrocatalytic ability of multilayer films based on [Fe(bpy)3]2+, and the Dawson heteropolyanion, [P2W18O62]6−

Electrocatalysis by crown-type polyoxometalates multi-substituted by transition metal ions; Comparative study

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