Reactions of Nitrosyls

Bottomley, Frank

doi:10.1007/978-1-4613-0755-6_3

Cited by 55 publications

(61 citation statements)

References 363 publications

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“…[11] The analytical applications for the determination of aqueous sulfide have been considered, [12] and the reaction was revisited [13] in the context of the interest in the nucleophilic additions of thiolates on the nitrosonium (NO + ) ligand in NP, forming iron-nitrosothiolates. [14,15] S-Nitrosothiols (RSNO) are involved in a variety of biological functions, as they can undergo transnitrosation reactions, release NO in the presence of reductants, and transfer nitrosonium (NO + ) or nitroxyl (NO À ) to substrates. As these processes may be metal-catalyzed, the coordination chemistry of nitrosothiols (or nitrososulfides) becomes biorelevant.…”

Section: N(oh)(s)(sh)]mentioning

confidence: 99%

Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

Quiroga

Almaraz

Amorebieta

et al. 2011

Chemistry A European J

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The nitroprusside ion [Fe(CN)(5)NO](2-) (NP) reacts with excess HS(-) in the pH range 8.5-12.5, in anaerobic medium ("Gmelin" reaction). The progress of the addition process of HS(-) into the bound NO(+) ligand was monitored by stopped-flow UV/Vis/EPR and FTIR spectroscopy, mass spectrometry, and chemical analysis. Theoretical calculations were employed for the characterization of the initial adducts and reaction intermediates. The shapes of the absorbance-time curves at 535-575 nm depend on the pH and concentration ratio of the reactants, R=[HS(-)]/[NP]. The initial adduct [Fe(CN)(5)N(O)SH](3-) (AH, λ(max) ≈570 nm) forms in the course of a reversible process, with k(ad)=190±20 M(-1)s(-1) , k(-ad)=0.3±0.05 s(-1) . Deprotonation of AH (pK(a)=10.5±0.1, at 25.0 °C, I=1 M), leads to [Fe(CN)(5)N(O)S](4-) (A, λ(max)=535 nm, ε=6000±300 M(-1) cm(-1) ). [Fe(CN)(5)NO](.)(3-) and HS(2)(.)(2-) radicals form through the spontaneous decomposition of AH and A. The minor formation of the [Fe(CN)(5)NO](3-) ion equilibrates with [Fe(CN)(4)NO](2-) through cyanide labilization, and generates the "g=2.03" iron-dinitrosyl, [Fe(NO)(2)(SH)(2)](-) , which is labile toward NO release. Alternative nucleophilic attack of HS(-) on AH and A generates the reactive intermediates [Fe(CN)(5)N(OH)(SH)(2)](3-) and [Fe(CN)(5)N(OH)(S)(SH)](4-) , respectively, which decompose through multielectronic nitrosyl reductions, leading to NH(3) and hydrogen disulfide, HS(2)(-) . N(2)O is also produced at pH≥11. Biological relevance relates to the role of NO, NO(-) , and other bound intermediates, eventually able to be released to the medium and rapidly trapped by substrates. Structure and reactivity comparisons of the new nitrososulfide ligands with free and bound nitrosothiolates are provided.

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Section: N(oh)(s)(sh)]mentioning

confidence: 99%

Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

Quiroga

Almaraz

Amorebieta

et al. 2011

Chemistry A European J

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“…Some of these transformations occur by direct oxidation, but transition metal ions are often required to activate nitric oxide. The disproportionation of NO is effected by a variety of metal complexes, , including those of iron, ruthenium, , cobalt , and copper. − …”

Section: Introductionmentioning

confidence: 99%

NO Disproportionation Reactivity of Fe Tropocoronand Complexes

1999

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The synthesis and characterization of divalent 5)] (1) and trivalent [Fe(OTf)(TC-5,5)] (2) tropocoronand complexes are described. Compound 1 reacts with 1 equiv of NO to form the {FeNO} 7 complex 3. A single-crystal X-ray structure determination of 3 reveals a trigonal bipyramidal geometry with a linearly coordinated nitrosyl (Fe-N-O ) 174.3(4)°) having a short Fe-N distance of 1.670(4) Å. EPR and Mo ¨ssbauer spectroscopy, SQUID susceptometry, and normal coordinate analysis indicate 3 to be a low-spin {Fe III (NO -)} 2+ species. In the presence of excess NO, 3 converts to a metastable nitrosyl-nitrito complex that decomposes by losing NO 2 , which subsequently nitrates the aromatic tropolone rings of the ligand. The final products of the NO disproportionation reaction are N 2 O and [Fe(NO)(TC-5,5-NO 2 )] (4). The ν NO stretching band of 4 is increased to 1716 cm -1 from its value of 1692 cm -1 in 3, owing to the electron-withdrawing nitro groups on the ligand, and the compound no longer promotes the disproportionation of NO. Mechanistic aspects of the reaction are discussed.

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“…The ability of transition metal complexes to interact with NO by either forming complexes with a variety of bonding modes or to perform deoxygenation reactions is well established for many metals and oxidation states. However, much less is known about the reactivity of the other nitrogen oxides.…”

Section: Introductionmentioning

confidence: 99%

One- vs Two-Electron Reduction of N₂O Promoted by a Divalent Chromium Macrocyclic Complex

et al. 1996

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Reaction of [Cr(ORPG)Li2(THF)4] (1) [ORPG = octaalkylporphyrinogen R = Et (a), n-Pr (b)] with N2O gave two different products depending on the solvent employed. While a deoxygenation reaction was observed in toluene with formation of the Cr(IV) complex [(THF)(ORPG)Cr(O)(LiTHF)2] (2), reactions carried out in THF yielded a Cr(III) species [Cr(ORPG)(THF)2][Li(THF)4] (3) where only one electron was transferred to N2O. The structures of 1b, 2a, and 3a have been elucidated by X-ray crystal structures. Crystal data are as follows. 1b: C60H96O4CrN4Li2, monoclinic P21/c, a = 20.504(2) Å, b = 12.347(1) Å, c = 22.524(1) Å, β = 94.56(1)°, Z = 4. 2a: C48H72O4CrN4Li2, monoclinic P21/n, a = 11.687(1) Å, b = 20.273(3) Å, c = 19.467(3) Å, β = 100.27(1)°, Z = 4. 3a: C60H96O6CrN4Li, monoclinic P21/c, a = 13.884(1) Å, b = 16.170(1) Å, c = 25.514(2) Å, β = 90.59(1)°, Z = 4.

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Reactions of Nitrosyls

Cited by 55 publications

References 363 publications

Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

NO Disproportionation Reactivity of Fe Tropocoronand Complexes

One- vs Two-Electron Reduction of N₂O Promoted by a Divalent Chromium Macrocyclic Complex

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Reactions of Nitrosyls

Cited by 55 publications

References 363 publications

Addition and Redox Reactivity of Hydrogen Sulfides (H2S/HS−) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

Addition and Redox Reactivity of Hydrogen Sulfides (H2S/HS−) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

NO Disproportionation Reactivity of Fe Tropocoronand Complexes

One- vs Two-Electron Reduction of N2O Promoted by a Divalent Chromium Macrocyclic Complex

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Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

Addition and Redox Reactivity of Hydrogen Sulfides (H₂S/HS⁻) with Nitroprusside: New Chemistry of Nitrososulfide Ligands

One- vs Two-Electron Reduction of N₂O Promoted by a Divalent Chromium Macrocyclic Complex