Three Redox States of Metallonitrosyls in Aqueous Solution

Bari, Sara E.; Iparraguirre, Jose Antonio Olabe; Slep, Leonardo D.

doi:10.1016/bs.adioch.2014.10.001

Cited by 20 publications

(56 citation statements)

References 212 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the latter case, the precursor can be either HNO, reaction (11), or 3 NO -, which reacts much faster (3 × 10 9 M -1 s -1 ). Finally, reaction (12) shows the reversible oxidative ability of HNO toward thiols (viz., as residues in proteins) that produces sulfenamide intermediates RSNHOH in the first step, followed by attack by a second RSH to give hydroxylamine (HA) and disulfides. Depending on concentrations, the process can evolve irreversibly giving sulfinamides RS(O)NH 2 .…”

Section: -mentioning

confidence: 99%

“…Depending on concentrations, the process can evolve irreversibly giving sulfinamides RS(O)NH 2 . [1,7] HNO + 2RSH ⇄ NH 2 OH + R 2 S 2 k 12 = 4.5 × 10 6 M -1 s -1 (12) Endogenous synthesis of HNO is feasible though controversial. [16,17] It might occur through similar oxidative routes as for NO-production through NOS, although by a four-electron oxidation under deficient conditions of the tetrahydrobiopterin (BH 4 ) cofactor.…”

Section: -mentioning

confidence: 99%

“…The three redox states of the nitrosyl diatomic group can be stabilized by complexation to metal ions. [12] NO binds covalently to transition metals M forming diverse structural types as mononuclear, NO-bridging and cluster compounds. We focus on mononuclear species with coordination numbers (CN) 6 and 5.…”

Section: Basic Transition Metal Coordination Chemistry Of No + No No - the Enemark-feltham Formalism And Beyondmentioning

confidence: 99%

“…Thus, the reactivity of "free" NO can be greatly modified upon coordination, as done by the multifunctional metalloenzymes necessary for the biosynthesis, transport, sensing and detoxification of NO. [6,10] Following a brief survey on the basic solution physical and chemical properties of NO, NO x and redox derivatives, [1,7] the coordination chemistry will be emphasized mainly by revisiting our work with a non-heme iron complex (pentacyanonitrosylferrate(II), "nitroprusside"), [11] and by using ruthenium nitrosyl models, [12] thus providing appropriate frameworks for comparison with the most biorelevant iron heme proteins. Recent aspects of the "crosstalk" of NO with H 2 S will be presented, comprising the intermediacy of thionitrous acid (NOSH), nitrososulfides (thionitrites, NOS -) and nitrosodisulfides (perthionitrites, NOS 2 -).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Coordination Chemistry of Nitric Oxide and Biological Signaling

Olabe

2020

scirevfew

View full text Add to dashboard Cite

Nitric Oxide (NO) is a key intermediate in the nitrogen redox cycles that operate in soils, water and biological fluids, affording reversible interconversions between nitrates to ammonia and vice-versa. The discovery of its biosynthesis in mammals for signaling purposes generated a research explosion on the ongoing chemistry occurring in specific cellular compartments, centered on NO reactivity toward O2, thiols, amines, and transition metals, as well as derivatives thereof. The present review deals with the coordination chemistry of NO toward selected iron and ruthenium centers. We place specific attention to the three redox states of the nitrosyl group: NO+, NO and NO–/HNO, describing changes in structure and reactivity as coordination takes place. Noteworthy are the results with the most reduced nitroxyl-species that allow establishing the changes in the measurable pKa values for the HNO-bound complexes, also revealing the abrupt decrease in reducing power and trans-releasing abilities of the protonated species over the unprotonated ones, NO–. Comparative results using non-heme and heme proteins and models prove useful for suggesting further improvements in the current research status of complex enzymatic behavior.

show abstract

Section: -mentioning

confidence: 99%

Section: -mentioning

confidence: 99%

Section: Basic Transition Metal Coordination Chemistry Of No + No No - the Enemark-feltham Formalism And Beyondmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Coordination Chemistry of Nitric Oxide and Biological Signaling

Olabe

2020

scirevfew

View full text Add to dashboard Cite

show abstract

“…[20] and at 1320 cm -1 . The latter band may be assigned to ν NO , as also observed in several reduced nitroso-derivatives [21][22][23].…”

Section: Successive Uv-vis Spectra Ph 11mentioning

confidence: 79%

The HNO donor ability of hydroxamic acids upon oxidation with cyanoferrates(III)

Gutiérrez

Almaraz

Bari

et al. 2015

Journal of Coordination Chemistry

Self Cite

View full text Add to dashboard Cite

The hydroxamic acids (RC(O)NHOH, HA) exhibit diverse biological activity, including hypotensive properties associated with formation of nitroxyl (HNO) or nitric oxide (NO). Oxidation of two HA's, benzohydroxamic and acetohydroxamic acids (BHA, AHA) by [Fe(CN) 5 NH 3 ] 2− or [Fe(CN) 6 ] 3− was analyzed by spectroscopic, mass spectrometric techniques, and flow EPR measurements. Mixing BHA with both Fe(III) reactants at pH 11 allowed detecting the hydroxamate radical, (C 6 H 5 )C(O)NO • − , as a 1-electron oxidation product, as well as N 2 O as a final product. Successive UV-vis spectra of mixtures containing [Fe(CN) 5 NH 3 ] 2− (though not [Fe(CN) 6 ] 3− ) at pH 11 and 7 revealed an intermediate acylnitroso-complex, [Fe(CN) 5 (NOC(O)(C 6 H 5 )] 3− (λ max , 465 nm, very stable at pH 7), formed through ligandinterchange in the initially formed reduction product, [Fe(CN) 5 NH 3 ] 3− , and characterized by FTIR spectra through the stretching vibrations ν (CN − ) , ν (CO) and ν (NO) . Free acylnitroso derivatives, formed by alternative reaction paths of the hydroxamate radicals, hydrolyze forming RC(O)OH and HNO, postulated as precursor of N 2 O. Minor quantities of NO are formed only with an excess of oxidant. The intermediacy of HNO was confirmed through its identification as [Fe(CN) 5 (HNO)] 3− (λ max , 445 nm) as a result of hydrolysis of [Fe(CN) 5 (NOC(O)(C 6 H 5 )] 3− at pH 11. The results demonstrate that hydroxamic acids behave predominantly as HNO-donors.

show abstract

Electrochemical Investigation of the Kinetics of Chloride Substitution upon Reduction of [Ru(porphyrin)(NO)Cl] Complexes in Tetrahydrofuran

et al. 2017

View full text Add to dashboard Cite

The electrochemistry of several ruthenium porphyrin nitrosyl chloride complexes [Ru(por)(NO)Cl] have been examined in tetrahydrofuran (THF). The complexes undergo one‐electron irreversible reductions, which result in diffusion‐limited substitutions of the chloride ligands for THF. This chloride metathesis is reversible in the presence of added NBu4Cl, and equilibrium constants and rate constants for chloride loss have been estimated. These parameters correlate with the NO stretching frequencies of the parent complexes, with more electron‐donating porphyrin ligands favoring chloride loss from the reduced complexes. The [Ru(por)(NO)(THF)] products of the reductions can be detected by IR, EPR, and visible spectroscopies. These species undergo three further reductions, with good reversibility at scan rates >0.40 V s−1. The [Ru(por) (NO)(THF)]+/0 couples have also been determined, and the rate constants and equilibrium constants for recombination with chloride have been estimated. One‐electron reductions of the [Ru(por)(NO)Cl] complexes result in approximately 1018 enhancement of the rates of chloride loss.

show abstract

Three Redox States of Metallonitrosyls in Aqueous Solution

Cited by 20 publications

References 212 publications

Coordination Chemistry of Nitric Oxide and Biological Signaling

Coordination Chemistry of Nitric Oxide and Biological Signaling

The HNO donor ability of hydroxamic acids upon oxidation with cyanoferrates(III)

Electrochemical Investigation of the Kinetics of Chloride Substitution upon Reduction of [Ru(porphyrin)(NO)Cl] Complexes in Tetrahydrofuran

Contact Info

Product

Resources

About