Solvent effects on the antioxidant activity of 3,4-dihydroxyphenylpyruvic acid : DFT and TD-DFT studies

Fifen, Jean Jules; Nsangou, Mama; Dhaouadi, Zoubeida; Motapon, Ousmanou; Jaı̈dane, N.

doi:10.1016/j.comptc.2011.03.006

Cited by 80 publications

(61 citation statements)

References 76 publications

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“…Hence, in contrast to the results published before (the scavenging of hydroxyl radical by DHPPA is governed by CPCET in nonpolar solvents and PT-ET mechanisms in polar solvents [3]), PT-ET mechanism may no longer be favored in polar solvents if coreactive species are taken into account.…”

Section: Pcet and Pt Mechanisms Via Somos Npascontrasting

confidence: 53%

“…Therefrom, it is noteworthy that the scavenging of hydroxyl radical by 3,4-DHPPA passes through a transition state (TS) while that of OBr − anion is barrierless. Moreover, it is well-known that the reaction of a phenolic acid (PhA) with neutral ROS leads to PCET mechanism while that with negatively charged ROS undergoes a barrierless PT mechanism [3,12,18,43,44]. This result may be generalized to PhAs which only have carbon, oxygen, and hydrogen in their skeleton (e.g., Quercetin may be a good candidate) and are involving the same RS or other.…”

Section: Resultsmentioning

confidence: 93%

“…Solvation free energies of the electron, proton, and hydrogen atom are, respectively, the free energies change of reactions below [3]: (21) where solvent (solv) represents a molecule of solvent in its cavity, X (solv) means that X is solvated, and solvent may be one of those used in this work. So, "solv" stands for cyclohexane, benzene, and so forth.…”

Section: Solvation Free Energies Of the Electron Protonmentioning

confidence: 99%

“…It is quite always an open problem. Recently, we studied the 3,4-dihydroxyphenylpyruvic acid (3,4-DHPPA) O-H bond cleavage in various media [3]. The scheme used in such a work does not consider the coreactive species (molecules or atoms which receive the transferred proton or hydrogen atom).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, metal ions effects on the antioxidant activity of 3,4-DHPPA were studied in the vacuum [18]. A conformational study of this acid was also undertaken [3] and the likeliest conformer is depicted in Figure 1. The…”

Section: Introductionmentioning

confidence: 99%

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Proton-Coupled Electron Transfer in the Reaction of 3,4-Dihydroxyphenylpyruvic Acid with Reactive Species in Various Media

Fifen

Dhaouadi

Nsangou

et al. 2015

International Journal of Chemical Physics

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The distinction of concerted proton-coupled electron transfer (CPCET) from sequential one as well as proton transfer-electron transfer (PT-ET) from electron transfer-proton transfer (ET-PT) in the O-H bond cleavage reactions in various media has always been a difficult task. In this work, the activation barrier of the CPCET mechanism, its rate constants, and reaction free energies related to ET-PT and PT-ET involving coreactive species were presented as good parameters to attempt the problem. DFT calculations were carried out studying the described pathways subsequent to the scavenging of• OH and OBr − by the 3,4-DHPPA in various media. The solvation was described in a hybrid manner using IEF-PCM model conjointly with a model that takes into account some solute-solvent interactions. As a result, we found that the scavenging of hydroxyl radical by 3,4-DHPPA is thermodynamically governed by a one-step hydrogen atom transfer (CPCET) from the acid to the radical in all media. In kinetic viewpoint, CPCET still dominates in the vacuum and in nonpolar solvents, but in polar solvents it could compete strongly with the ET-PT mechanism so that the latter could slightly dominate.

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Section: Pcet and Pt Mechanisms Via Somos Npascontrasting

confidence: 53%

Section: Resultsmentioning

confidence: 93%

Section: Solvation Free Energies Of the Electron Protonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Proton-Coupled Electron Transfer in the Reaction of 3,4-Dihydroxyphenylpyruvic Acid with Reactive Species in Various Media

Fifen

Dhaouadi

Nsangou

et al. 2015

International Journal of Chemical Physics

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Large‐Sized Ammonia Clusters and Solvation Energies of the Proton in Ammonia

2019

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The absolute solvation energies (free energies and enthalpies) of the proton in ammonia are used to compute the pKa of species embedded in ammonia. They are also used to compute the solvation energies of other ions in ammonia. Despite their importance, it is not possible to determine experimentally the solvation energies of the proton in a given solvent. We propose in this work a direct approach to compute the solvation energies of the proton in ammonia from large‐sized neutral and protonated ammonia clusters. To undertake this investigation, we performed a geometry optimization of neutral and protonated ammonia 30‐mer, 40‐mer, and 50 mer to locate stable structures. These structures have been fully optimized at both APFD/6‐31++g(d,p) and M06‐2X/6‐31++g(d,p) levels of theory. An infrared spectroscopic study of these structures has been provided to assess the reliability of our investigation. Using these structures, we have computed the absolute solvation free energy and the absolute solvation enthalpy of the proton in ammonia. It comes out that the absolute solvation free energy of the proton in ammonia is calculated to be −1192 kJ mol–1, whereas the absolute solvation enthalpy is evaluated to be −1214 kJ mol–1. © 2019 Wiley Periodicals, Inc.

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Synthesis, antioxidant and anticholinesterase activities of novel quinoline‐aminophosphonate derivatives

Bazine

Cheraiet

Bensegueni

et al. 2020

Journal of Heterocyclic Chem

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A series of 20 novel α-aminophosphonate derivatives bearing quinoline or quinolone moiety was designed and synthesized via Kabachnik-Fields reaction in the presence of triethylammonium acetate as a solvent and catalyst under ultrasound irradiation. This procedure affords products in high yields and short reaction times. Molecular structures of the synthesized compounds 4a-g and 5a-m were confirmed using various spectroscopic methods. The antioxidant activity of these compounds was evaluated by eight complementary in vitro tests. The anticholinesterase activity (AChE, BChE) of these compounds were also evaluated. In addition, theoretical calculations of all compounds were investigated as corrosion inhibitors using density functional theory (DFT). The results revealed that 16 of these compounds exhibited high levels of antioxidant activities depending on the assay and that most compounds showed more potent inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE).H NMR (400 MHz, Chloroform-d 6 ) δ 11.75 (s, 1H, OH), 9.74 (s, 1H, NH), 7.70 (d, J H-P = 3.5 Hz, 1H Ar, H 7 ), 7.10-7.00 (m, 2H Ar, H 1 , H 3, ), 6.93 (dd, J ortho = 8.2, J metha = 1.5 Hz, 1H Ar, H 6 ), 6.88 (dd, J ortho = 7.8, J metha = 1.4 Hz, 1H Ar, H 17 ), 6.72 (td, J ortho = 7.7, J metha = 1.9 Hz, 1H Ar, H 2 ), 6.54 (td, J ortho = 7.6, J metha = 1.4 Hz, 1H Ar, H 18 ), 6.50 (dd, J ortho = 8.4, J metha = 3.6 Hz, 1H Ar, H 16 ), 5.92(d, J = 11.6 Hz, 1H, NH), 5.89(dd, J ortho = 7.8, J metha = 1.7 Hz, 1H, H 15 ), 5.77 (dd, J H-P = 25.0, 11.6 Hz, 1H, H 12 ), 4. 46-4.33 (m, 2H, H 27 ), 4.16-3.91 (m, 2H, H 24 ), 1.20 (t, J = 7.0 Hz, 3H Ar,

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Solvent effects on the antioxidant activity of 3,4-dihydroxyphenylpyruvic acid : DFT and TD-DFT studies

Cited by 80 publications

References 76 publications

Proton-Coupled Electron Transfer in the Reaction of 3,4-Dihydroxyphenylpyruvic Acid with Reactive Species in Various Media

Proton-Coupled Electron Transfer in the Reaction of 3,4-Dihydroxyphenylpyruvic Acid with Reactive Species in Various Media

Large‐Sized Ammonia Clusters and Solvation Energies of the Proton in Ammonia

Synthesis, antioxidant and anticholinesterase activities of novel quinoline‐aminophosphonate derivatives

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