Disproportionation Of Nitric Oxide Research Articles

Electrocatalytic Disproportionation of Nitric Oxide Toward Efficient Nitrogen Fixation (Adv. Energy Mater. 14/2023)

Nitrogen Fixation In article number 2204231, Angjian Wu, Hao Bin Wu, Jianhua Yan, and co-workers achieve electrocatalytic disproportionation of nitric oxide in a bipolar membrane based electrolysis system with decoupled acid–base electrolytes, which aims for efficient nitrogen fixation via coupling the cathodic NO reduction reaction with the anodic NO electrooxidation simultaneously.

Nitric Oxide Disproportionation Mediated by a Rh Complex with an Asymmetric Pincer Ligand: Spectroscopic Detection of a Dinitrosyl Intermediate

AbstractThe disproportionation of nitric oxide was studied by FTIR with two different Rh(I)PCN complexes as mediators (PCN 1‐((diethylamino)methyl)‐3‐((di‐tertbutylphosphino)methyl)‐benzene). As had already been reported for a PCP analogue, reaction yielded a Rh(PCN)(NO)(NO2) complex along with gaseous N2O in both cases. However, when [Rh(PCN)(NO)]⋅ was used as a reactant, FTIR monitoring allowed for the detection of signals of a reaction intermediate, coherent with the expected but seldom reported dinitrosyl species Rh(PCN)(NO)(NO). DFT studies on this species revealed that pincer hemilability of the amino arm is involved in its stabilization, therefore accounting for the differences observed in reactivity between PCN and PCP.

Disproportionation of Nitric Oxide at a Surface-Bound Nickel Porphyrinoid.

Uncommon metal oxidation states in porphyrinoid cofactors are responsible for the activity of many enzymes. The F430 and P450nor co‐factors, with their reduced NiI‐ and FeIII‐containing tetrapyrrolic cores, are prototypical examples of biological systems involved in methane formation and in the reduction of nitric oxide, respectively. Herein, using a comprehensive range of experimental and theoretical methods, we raise evidence that nickel tetraphenyl porphyrins deposited in vacuo on a copper surface are reactive towards nitric oxide disproportionation at room temperature. The interpretation of the measurements is far from being straightforward due to the high reactivity of the different nitrogen oxides species (eventually present in the residual gas background) and of the possible reaction intermediates. The picture is detailed in order to disentangle the challenging complexity of the system, where even a small fraction of contamination can change the scenario.

Disproportionation of Nitric Oxide at a Surface-Bound Nickel Porphyrinoid.

Uncommon metal oxidation states in porphyrinoid cofactors are responsible for the activity of many enzymes. The F430 and P450nor co-factors, with their reduced NiI- and FeIII-containing tetrapyrrolic cores, are prototypical examples of biological systems involved in methane formation and in the reduction of nitric oxide, respectively. Herein, using a comprehensive range of experimental and theoretical methods, we raise evidence that nickel tetraphenyl porphyrins deposited in vacuo on a copper surface are reactive towards nitric oxide disproportionation at room temperature. The interpretation of the measurements is far from being straightforward due to the high reactivity of the different nitrogen oxides species (eventually present in the residual gas background) and of the possible reaction intermediates. The picture is detailed in order to disentangle the challenging complexity of the system, where even a small fraction of contamination can change the scenario.

Oxygen and nitrogen production by an ammonia-oxidizing archaeon.

Ammonia-oxidizing archaea (AOA) are one of the most abundant groups of microbes in the world’s oceans and are key players in the nitrogen cycle. Their energy metabolism—the oxidation of ammonia to nitrite—requires oxygen. Nevertheless, AOA are abundant in environments where oxygen is undetectable. By carrying out incubations for which oxygen concentrations were resolved to the nanomolar range, we show that after oxygen depletion, Nitrosopumilus maritimus produces dinitrogen and oxygen, which is used for ammonia oxidation. The pathway is not completely resolved but likely has nitric oxide and nitrous oxide as key intermediates. N. maritimus joins a handful of organisms known to produce oxygen in the dark. On the basis of this ability, we reevaluate the role of N. maritimus in oxygen-depleted marine environments.

Computational Exploration of NO Single-Site Disproportionation on Fe-MOF-5

Nitric oxide disproportionation at the site-isolated Fe centers of the metal organic framework material known as Fe-MOF-5 has been explored with density functional theory (DFT). The computed reacti...

Nitric Oxide Generation On Demand for Biomedical Applications via Electrocatalytic Nitrite Reduction by Copper BMPA- and BEPA-Carboxylate Complexes.

Intravascular (IV) catheters are essential devices in the hospital that are used to monitor a patient's blood and for administering drugs or nutrients. However, IV catheters are also prone to blood clotting at the point of insertion and infection by formation of robust bacterial biofilms on their surface. Nitric oxide (NO) is ideally suited to counteract both of these problems, due to its antimicrobial properties and its ability to inhibit platelet activation/aggregation. One way to equip catheters with NO releasing properties is by electrocatalytic nitrite reduction to NO by copper complexes in a multi-lumen configuration. In this work, we systematically investigate six closely related Cu(II) BMPA- and BEPA-carboxylate complexes (BMPA = bis-(2-methylpyridyl)amine); BEPA = bis-(2-ethylpyridyl)amine), using carboxylate groups of different chain lengths. The corresponding Cu(II) complexes were characterized using UV-Vis, EPR spectroscopy, and X-ray crystallography. Using detailed cyclic voltammetry (CV) and bulk electrocatalyic studies (with real-time NO quantification), in aqueous buffer, pH 7.4, we are able to derive clear reactivity relations between the ligand structures of the complexes, their Faradaic efficiencies for NO generation, their turnover frequencies (TOFs), and their redox potentials. Our results show that the complex [Cu(BEPA-Bu)](OAc) is the best catalyst with a high Faradaic efficiency over large nitrite concentration ranges and the expected best tolerance to oxygen levels. For this species, the more positive redox potential suppresses NO disproportionation, which is a major Achilles heel of the (faster) catalysts with the more negative reduction potentials.

Reductive disproportionation of nitric oxide mediated by low-valent uranium.

The reductive disproportionation of nitric oxide (1 atm) is mediated by the bulky U(III) aryloxide [U(III)(OAr(Ad,Ad,Me))3] ((Ad,Ad,Me)ArO = O-C6H2-2,6-Ad-4-Me) (1) to form the U(V) terminal oxo species [((Ad,Ad,Me)ArO)3U(V)(O)] (2) and N2O, as confirmed by single crystal X-ray diffraction and GC-MS measurements. The reaction is quantitative in the solid state. Mechanistic and theoretical studies of the reaction suggest that the N-N bond is formed by the coupling of an η(1)-O bound nitric oxide ligand with gaseous NO to give an η(1)-(N2O2)(1-) intermediate prior to the spontaneous extrusion of N2O to yield the U(V) terminal oxo species 2.

Mechanistic Insights into the Formation of N2O by a Nickel Nitrosyl Complex

Reaction of [Ni(NO)(bipy)(Me2phen)][PF6] with 1 equiv of nitric oxide (NO) in CH2Cl2 results in the formation of N2O and [{(Me2phen)Ni(NO)}2(μ-η(1)-N:η(1)-O)-NO2)][PF6] (3), along with the known complex, [Ni(bipy)3][PF6]2 (4). The isolation of complex 3, which contains a nitrite ligand, demonstrates that the reaction of [Ni(NO)(bipy)(Me2phen)][PF6] with exogenous NO results in NO disproportionation and not NO reduction. Complex 3 could also be accessed by reaction of [Ni(NO)(Me2phen)][PF6] (5) with (Me2phen)Ni(NO)(NO2) (7) in good yield. Complexes 3, 5, and 7 were fully characterized, including analysis by X-ray crystallography in the case of 3 and 7. Furthermore, addition of 0.5 equiv of bipy to [Ni(NO)(bipy)][PF6] results in formation of the hyponitrite complex, [{(bipy)Ni(κ(2)-O2N2)}η(1):η(1)-N,N-{Ni(NO)(bipy)}2][PF6]2 (9), in modest yield. Importantly, the hyponitrite ligand in 9 is thought to form via coupling of two NO(-) ligands and not by coupling of a nucleophilic nitrosyl ligand (NO(-)) with an electrophilic nitrosyl ligand (NO(+)). X-ray crystallography reveals that complex 9 features a new binding mode of the cis-hyponitrite ligand.

Tracking Reactive Intermediates by FTIR Monitoring of Reactions in Low-Temperature Sublimed Solids: Nitric Oxide Disproportionation Mediated by Ruthenium(II) Carbonyl Porphyrin Ru(TPP)(CO)

Interaction of NO ((15)NO) with amorphous layers of Ru(II) carbonyl porphyrin (Ru(TPP)(CO), TPP(2-) = meso-tetraphenylporphyrinato dianion) was monitored by FTIR spectroscopy from 80 K to room temperature. An intermediate spectrally characterized at very low temperatures (110 K) with ν(CO) at 2001 cm(-1) and ν(NO) at 1810 cm(-1) (1777 cm(-1) for (15)NO isotopomer) was readily assigned to the mixed carbonyl-nitrosyl complex Ru(TPP)(CO)(NO), which is the logical precursor to CO labilization. Remarkably, Ru(TPP)-mediated disproportionation of NO is seen even at 110 K, an indication of how facile this reaction is. By varying the quantity of supplied NO, it was also demonstrated that the key intermediate responsible for NO disproportionation is the dinitrosyl complex Ru(TPP)(NO)2, supporting the conclusion previously made from solution experiments.

Nitric Oxide Disproportionation at Mild Temperatures by a Nanoparticulate Cobalt(II) Complex

Nanoparticles of CoII(salen) exhibit a 32% mass change when exposed to flowing nitric oxide at room temperature. Control experiments indicate that the large uptake of NO occurs only in the nanoparticles. Nitric oxide disproportionation is proposed to account for these observations, which is supported by spectroscopic measurements showing the presence of N2O and N2.

Low temperature NO disproportionation by Mn porphyrin. Spectroscopic characterization of the unstable nitrosyl nitrito complex MnIII(TPP)(NO)(ONO).

Reaction of NO gas with sublimed layers of the Mn(II)TPP (TPP =meso-tetraphenylporphyrinato2-) at low temperature leads to nitric oxide disproportionation. UV-Vis and FTIR spectroscopy with isotopically substituted nitrogen oxides revealed formation of the unstable species identified as trans-Mn(III)(TPP)(NO)(ONO).

Synthesis, characterization, and molecular structures of nitrosyl nitrito complexes of osmium porphyrins: Disproportionation of nitric oxide in its reaction with Os(P)(CO) (P = porphyrinato dianion)

The Os(P)(NO)(ONO) compounds (P = TTP, TMP, OEP, TmTP; TTP = 5,10,15,20-tetra-p-tolylporphyrinato dianion, TMP = 5,10,15,20-tetramesitylporphyrinato dianion, OEP = octaethylporphyrinato dianion, TmTP = tetra(m-tolyl)porphyrinato dianion) have been prepared from the reaction of the precursor carbonyl complexes Os(P)(CO) with excess nitric oxide. Nitrous oxide was detected as a by-product of the reaction. The IR spectra of the Os(P)(NO)(ONO) compounds (as KBr pellets) reveal bands in the 1790–1804 cm–1 range that are assigned to υNO. The IR spectra also reveal two new bands for each complex in the 1495–1531 and 913–962 cm–1 ranges indicative of O-bound nitrito ligands. The linearity of the bound NO groups and the O-binding of the trans nitrito ligands in the Os(P)(NO)(ONO) complexes are evident in the single-crystal X-ray crystal structures of the TTP and TMP derivatives. The kinetics of the reaction were studied by stopped-flow mixing techniques. Spectroscopic analysis of rapidly mixed solutions of Os(P)CO and NO in toluene showed a biphasic approach to the Os(P)(NO)(ONO) and N2O products, owing to the starting material Os(P)CO scavenging CO formed during the reaction to give Os(P)(CO)2 (KCO = 106 M–1). The dicarbonyl was the only transient species observed. It is proposed that the rate-determining step of the reaction leading to Os(P)(NO)(ONO) is NO displacement of CO from Os(P)(CO) via initial formation of an unstable 19 electron Os(P)(NO)(CO) intermediate.Key words: osmium, nitric oxide, X-ray, nitrosyl, porphyrin, kinetics.

Gas-phase Disproportionation of Nitric Oxide at Elevated Pressures

T.P. Melia's chemical kinetics study of the disproportionation of nitric oxide (NO), 3NO M NO2 + N2O, (Melia, T.P. (1965) J. Inorg. Nucl. Chem., 27, 95-98), which is the most quoted quantitative investigation presently available, revealed a rather strong dependence of the effective rate constant, Kk ', of Melia's third-order rate law,- d[NO]/d t = Kk'[NO]3, on the initial pressure of NO. In order to estimate extent of accumulation of NO2 and N2O as a function of time by integration of the rate law, we have evaluated the dependence of the effective rate constant as a function of pressure and thus as a function of time on the basis of the non-ideality of NO gas. Although our approach is crude in that the non-idealities of NO2 and N2O and other NOx products and a probable deviation of the gas mixture from the Dalton's law have not been considered, it provides a means for approximately estimating the rate of accumulation of NO2 and N2O based on Melia's data. According to these calculations, the extent of the disproportionation is generally negligible at low initial pressures, e.g. 5 atm or less, while at 200 atm, the mole fractions of NO2 and N2O can become as high as 12-13% only after 10 days. These values are alarmingly high for handling pressured NO- in N2-mixture in either research or clinical settings. This information must be borne in mind when compressed NO in commercial cylinders is employed in high precision experiments. Disproportionation of NO under pressure also deserves attention in inhalation of low doses of NO in the treatment of diseases characterized by pulmonary hypertension and hypoxemia.

Gas-phase oxidation and disproportionation of nitric oxide

Gas-phase oxidation and disproportionation of nitric oxide

Kinetics and Mechanism of Nitric Oxide Disproportionation upon Reaction with Ruthenium(II) Porphyrin Carbonyls:  Evidence for Dinitrosyl Intermediates1

The kinetics of the reaction of nitric oxide with the ruthenium porphyrin carbonyl complexes Ru(P)(CO) (P = octaethylporphyrin (OEP) or tetra-m-tolylporphine (TmTP)) to give the respective nitrosyl...

Disproportionation of Nitric Oxide Promoted by a Mn Tropocoronand

The synthesis and characterization of the divalent tropocoronand, [Mn(THF)(TC-5,5)] (1), are described. Compound 1 reacts with NO to afford a discrete mononitrosyl [Mn(NO)(TC-5,5)] (2), which was isolated and shown formally to contain the {MnIIINO-}2+ fragment by infrared spectroscopy, normal coordinate analysis, X-ray crystallography, and SQUID susceptometry. The Mn center in 2 has idealized trigonal bipyramidal geometry with the NO ligand occupying a coordination site in the equatorial plane. The Mn−N−O bond angle is nearly linear, 174.1(3)°. Compounds 1 and 2 react with excess NO to afford N2O and [Mn(NO2)(TC-5,5)] (3). The X-ray structure of 3 reveals coordination of the nitrito ligand through one oxygen atom, the Mn−O bond length being 2.09(4) A. The other oxygen atom interacts weakly with the manganese center at a distance of 2.61(5) A. Quantitation by gas chromatographic analysis of released N2O confirms that 1 equiv forms for each molecule of 2 which converts to 3. Infrared spectroscopic experimen...

Reaction mechanisms for the reduction of nitric oxide by hydrocarbons on Cu-ZSM-5 and related catalysts

In this letter, an overview of the literature on the reaction mechanism of the reduction of nitric oxide by hydrocarbons in presence of oxygen is given. It is followed by a discussion of some organic chemistry literature. A new reaction mechanism is proposed which combines two of the reaction mechanisms proposed in the literature and involves a nitroso-intermediate which initiates a radical chain mechanism which leads to the disproportionation of nitric oxide into nitrogen and nitrogen dioxide. Finally, the reaction mechanisms proposed until now are compared.

ChemInform Abstract: DISPROPORTIONATION OF NITRIC OXIDE AT HIGH PRESSURE

AbstractBei 176 K und 1.5 GPa disproportioniert′ N2O2 leicht und vollständig.

Disproportionation of nitric oxide at high pressure

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDisproportionation of nitric oxide at high pressureStephan F. Agnew, B. I. Swanson, L. H. Jones, and R. L. MillsCite this: J. Phys. Chem. 1985, 89, 9, 1678–1682Publication Date (Print):April 1, 1985Publication History Published online1 May 2002Published inissue 1 April 1985https://doi.org/10.1021/j100255a026RIGHTS & PERMISSIONSArticle Views299Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (595 KB) Get e-Alerts