The use of cyclic nitroxide radicals as HNO scavengers

Samuni, Yuval; Samuni, Uri; Goldstein, Sara

doi:10.1016/j.jinorgbio.2012.10.002

Cited by 21 publications

(15 citation statements)

References 59 publications

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“…Insights into the unique properties of the nitroxyl/NO x cocatalyst combination can be gleaned from the data above as well as previous literature, 36 − 40 and the tandem catalytic cycle in Scheme 4 provides the basis for our analysis. At the electrode, TEMPO + is reduced to TEMPO radical, which may be reoxidized by NO 2 to close the left-hand cycle.…”

Section: Resultsmentioning

confidence: 99%

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

Gerken

Stahl

2015

ACS Cent. Sci.

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Efficient reduction of O2 to water is a central challenge in energy conversion and many aerobic oxidation reactions. Here, we show that the electrochemical oxygen reduction reaction (ORR) can be achieved at high potentials by using soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO), nor NOx species, such as sodium nitrite, are effective ORR mediators. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction with overpotentials as low as 300 mV in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The overpotentials accessible with this ORR system are significantly lower than widely studied molecular metal-macrocycle ORR catalysts and benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls.

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Section: Resultsmentioning

confidence: 99%

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

Gerken

Stahl

2015

ACS Cent. Sci.

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“…The concentrations were determined based on the calibration curves obtained for the authentic standards. tally using the published rate constants for selected scavengers of HNO (CPTIO, PTIO, TEMPOL, superoxide dismutase, and HRP) (36,40,41). From obtaining the mean of values ( (Table 3).…”

Section: Journal Of Biological Chemistry 35575mentioning

confidence: 99%

“…Although the high reactivity of HNO toward cellular thiols and metal centers could classify this species as a potential signaling molecule (32), the lack of information concerning its endogenous biosynthetic pathways questions its biological relevance. Nitroxides and nitronyl nitroxides are also commonly used HNO scavengers (36,40,41).…”

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confidence: 99%

Nitroxyl (HNO) Reacts with Molecular Oxygen and Forms Peroxynitrite at Physiological pH

Smulik

Dębski

Zielonka

et al. 2014

Journal of Biological Chemistry

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Background: Nitroxyl (HNO) is a reactive nitrogen species implicated in cardioprotection. Results: Nitroxyl reacts with oxygen to form an oxidizing and nitrating species, peroxynitrite. Conclusion: In the presence of oxygen, HNO donors may be a source of peroxynitrite. Significance: Peroxynitrite formation should be taken into account in the extracellular milieu when exposing cells to HNO donor under aerobic conditions.

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“…Nitroxyl reacts with stable nitroxide free radicals such as (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl (TEMPO) with rate constants of 10 4 -10 5 M Ϫ1 s Ϫ1 forming the hydroxylamine and NO ⅐ (Fig. 5F) (162,163). Fluorogenic TEMPO derivatives have been prepared in which the nitroxide group quenches the fluorescence, which is released when the nitroxide is converted to the hydroxylamine (160,164).…”

Section: Detection Of Nitroxylmentioning

confidence: 99%

Detection and quantification of nitric oxide–derived oxidants in biological systems

Möller

Ríos

Trujillo

et al. 2019

Journal of Biological Chemistry

128

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Edited by Ruma Banerjee The free radical nitric oxide (NO ⅐) exerts biological effects through the direct and reversible interaction with specific targets (e.g. soluble guanylate cyclase) or through the generation of secondary species, many of which can oxidize, nitrosate or nitrate biomolecules. The NO ⅐-derived reactive species are typically short-lived, and their preferential fates depend on kinetic and compartmentalization aspects. Their detection and quantification are technically challenging. In general, the strategies employed are based either on the detection of relatively stable end products or on the use of synthetic probes, and they are not always selective for a particular species. In this study, we describe the biologically relevant characteristics of the reactive species formed downstream from NO ⅐ , and we discuss the approaches currently available for the analysis of NO ⅐ , nitrogen dioxide (NO 2 ⅐), dinitrogen trioxide (N 2 O 3), nitroxyl (HNO), and peroxynitrite (ONOO ؊ /ONOOH), as well as peroxynitrite-derived hydroxyl (HO ⅐) and carbonate anion (CO 3 ⅐ ؊) radicals. We also discuss the biological origins of and analytical tools for detecting nitrite (NO 2 ؊), nitrate (NO 3 ؊), nitrosyl-metal com

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The use of cyclic nitroxide radicals as HNO scavengers

Cited by 21 publications

References 59 publications

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

Nitroxyl (HNO) Reacts with Molecular Oxygen and Forms Peroxynitrite at Physiological pH

Detection and quantification of nitric oxide–derived oxidants in biological systems

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The use of cyclic nitroxide radicals as HNO scavengers

Cited by 21 publications

References 59 publications

High-Potential Electrocatalytic O2Reduction with Nitroxyl/NOxMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

High-Potential Electrocatalytic O2Reduction with Nitroxyl/NOxMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

Nitroxyl (HNO) Reacts with Molecular Oxygen and Forms Peroxynitrite at Physiological pH

Detection and quantification of nitric oxide–derived oxidants in biological systems

Contact Info

Product

Resources

About

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

High-Potential Electrocatalytic O₂Reduction with Nitroxyl/NO_xMediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis