Proton–coupled electron transfer versus hydrogen atom transfer: A density functional reactivity theory characterization

Zhong, Aiguo; Ge, Canghua; Liang, Huading; Jiang, Huajiang; Zhou, Qizhong

doi:10.1016/j.comptc.2012.02.020

Cited by 4 publications

(2 citation statements)

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“…The positive part of f – ( r ), which appeared as a green isosurface on C2, C4, and C5 (Figure b), was the main attack site of the electrophiles, which indicated the same electrophilic attack site as [HHIM] + , [HMIM] + , [DMIM] + , and [TMIM] + . Obviously, the change in the protonation and symmetry of the imidazolium structure did not alter the potential attack site of • OH.…”

Section: Resultsmentioning

confidence: 99%

“…C4 and C5 were more susceptible to be attacked by • OH than C2 because the Δf(r) values of C4 and C5 were negative (blue isosurface) while that of C2 was positive (green isosurface) (Figure S4). 25,26 Protic [HHIM] + had greater condensed f A − and more negative condensed Δf A at each atom than aprotic [DMIM] + and [TMIM] + (Figure 1c,d, Table S4), 26−28 which suggested its high reactivity of each atom on [HHIM] + with • OH. The result was connected to the greater TOC%, k 0,TOC and k 0 of [HHIM] + than those of [DMIM] + and [TMIM] + .…”

Section: While [Dmim][bf 4 ] and [Tmim]-[bfmentioning

confidence: 99%

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Structure-Dependent Fenton Reactivity and Degradation Pathway of Methylimidazolium Ionic Liquids

et al. 2020

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Short-chain imidazolium-based ionic liquids (IBILs) substituted by methyl groups are highly water-soluble and have the potential risk of entering the water environment with wastewater. In this work, the structure-dependent Fenton reactivity and degradation pathway of methylimidazolium ionic liquids were investigated, including the influence of the proton activity and structural symmetry of IBILs. The chemical reactivity of specific sites (atoms) was quantitatively predicted by a condensed Fukui function (f A − ). Aprotic IBILs ([DMIM][BF 4 ] and [TMIM][BF 4 ]) were more resistant to the • OH attacks than protic IBILs ([HHIM][BF 4 ] and [HMIM][BF 4 ]) because deprotonation reduced the f A − value of the attack sites. Structural symmetry increased the initial rate of the total organic carbon (TOC) reduction (k 0,TOC ) due to the existence of symmetric Fenton reaction sites. Trimethyl-substituted [TMIM][BF 4 ] showed the lowest TOC removal efficiency and k 0,TOC presumably because the C2methyl substitution greatly weakened the f A − value of C2. The plausible mineralization pathways were proposed on the basis of gas chromatography coupled with mass spectrometry analyses. The more methyl substitution resulted in weaker Fenton reactivity but more oxidation pathways. For [TMIM][BF 4 ], C2-methyl reduced the Fenton reactivity of the imidazolium skeleton but increased the oxidation opportunities of dual N-methyls.

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Section: Resultsmentioning

confidence: 99%

Section: While [Dmim][bf 4 ] and [Tmim]-[bfmentioning

confidence: 99%

Structure-Dependent Fenton Reactivity and Degradation Pathway of Methylimidazolium Ionic Liquids

et al. 2020

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The DFT local reactivity descriptors of α-tocopherol

2015

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The calculations of local reactivity descriptors, the electron donor Fukui function f(-)(r), the average local ionization energy Ī(r), the Fukui function dual descriptor f((2))(r), and the electron acceptor Fukui function f(+)(r) for α-tocopherol, the main biologically active form of vitamin E for antioxidant reactions in phospholipid membranes, is presented. The calculations are performed at B3LYP/6-311++G** level of theory in the gas-phase. The obtained results indicate that the most preferred sites for donating electron in a reaction with radical or oxidizing molecule are associated mostly with π electrons above and below the aromatic part of the α-tocopherol chromanol ring. The most reactive sites for accepting electrons are associated with the leaving H(9) atom in the extension of the phenolic OH bond on the α-tocopherol chromanol ring plane, in the place where the formation of H-bond of the precursor complex between approaching reactive oxygen radical and phenolic OH group of α-tocopherol could be expected. The separated reactive sites in α-tocopherol suggest that the proton and electron, along with the hydrogen atom transfer (HAT) process, could also be transferred to different proton and electron acceptors as in bidirectional proton coupled electron transfer (PCET) reactions. The results presented in this paper suggest that large charge redistribution and significant π-π interactions may be expected in antioxidant reactions of α-tocopherol.

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Theoretical studies on the proton-transfer reactions in propylene and pentadiene derivatives

Sun

2014

Struct Chem

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Proton–coupled electron transfer versus hydrogen atom transfer: A density functional reactivity theory characterization

Cited by 4 publications

References 48 publications

Structure-Dependent Fenton Reactivity and Degradation Pathway of Methylimidazolium Ionic Liquids

Structure-Dependent Fenton Reactivity and Degradation Pathway of Methylimidazolium Ionic Liquids

The DFT local reactivity descriptors of α-tocopherol

Theoretical studies on the proton-transfer reactions in propylene and pentadiene derivatives

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