Electron Transfer Initiated Reactions: Bond Formation and Bond Dissociation

Houmam, Abdelaziz

doi:10.1021/cr068070x

Cited by 236 publications

(182 citation statements)

References 817 publications

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“…SET is a key step in numerous reactions and has been intensively investigated both experimentally and theoretically [26,27]. Bimolecular electron transfer takes place when an electron-rich donor encounters an electron-poor acceptor.…”

Section: Introductionmentioning

confidence: 99%

N-Centered Odd-Electron Ions Formation from Collision-Induced Dissociation of Electrospray Ionization Generated Even-Electron Ions: Single Electron Transfer via Ion/Neutral Complex in the Fragmentation of ProtonatedN,N′-Dibenzylpiperazines and ProtonatedN-Benzylpiperazines

Chai

Sun

Pan

et al. 2011

J. Am. Soc. Mass Spectrom.

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Single electron transfer (SET) via ion/neutral complex (INC) was proposed and confirmed to be the key step in the formation of N-centered odd-electron ions from fragmentation of protonated even-electron ions in the present study. Upon collisional activation, the model compounds, protonated N,N′-dibenzylpiperazine and protonated N-benzylpiperazines initially dissociated to form intermediate INCs consisting of N-benzylpiperazine (or piperazine) and benzyl cation. In these ion/neutral complexes, SET reaction and direct separation as well as other reactions were observed and characterized experimentally and theoretically. Density functional theory calculations demonstrated that the energy requirement for homolysis of the precursor ion was so large that it could not be achieved, whereas the heterolytic dissociation followed by electron transfer via INC was energetically preferred. The SET process occurred only when the radical products were more stable than the separation products. The energy barrier for SET in the compounds studied was roughly estimated by comparison with other competing reactions. When the INC contained electron donor with lower ionization energy and electron acceptor with higher electron affinity, the SET reaction was more efficient.

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Section: Introductionmentioning

confidence: 99%

N-Centered Odd-Electron Ions Formation from Collision-Induced Dissociation of Electrospray Ionization Generated Even-Electron Ions: Single Electron Transfer via Ion/Neutral Complex in the Fragmentation of ProtonatedN,N′-Dibenzylpiperazines and ProtonatedN-Benzylpiperazines

Chai

Sun

Pan

et al. 2011

J. Am. Soc. Mass Spectrom.

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“…5) correspond to 0.31 and 0.28, respectively. These values are much lower than 0.5 which indicates that the reduction reaction is kinetically controlled by the electron transfer step (1)(2)(3)14,15). A second irreversible peak is observed upon scanning to more negative potentials at Ep = -2.35 V vs SCE and corresponds to the reduction of the iodophenyl moiety associated with the cleavage of the C-I chemical bond.…”

Section: Resultsmentioning

confidence: 94%

Electrochemical Reduction of 4-Iodophenyl Sulfonyl Chloride

Hamed

Houmam

2011

ECS Trans.

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Important aspects of the electrochemical reduction of 4-iodophenyl sulfonyl chloride are investigated in acetonitrile at a glassy carbon electrode. The first electron transfer follows a concerted process where the S-Cl chemical bond is cleaved upon injection of the first electron. An interesting autocatalytic mechanism is encountered and the 4-iodophenyl sulfonyl chloride is reduced both at the electrode and through homogeneous electron transfer from the resulting sulfinate anion. An electron transfer between the generated sulfinate anion and the parent molecule is the basis to the observed autocatalytic process. Consequently, the reduction process depends on both the concentration of the substrate and the scan rate. Gas phase chemical quantum calculations results help to rationalize the mechanism of the first electron transfer.

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“…Electrochemistry provides very versatile means for the electrosynthesis and mechanistic studies [1][2][3][4][5][6]. Using electrochemical methods with a wide time window (submicroseconds to hours) thermodynamic and kinetic information about the reactions of organic and inorganic species were obtained [7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic study of electrochemical oxidation of 2,5-diethoxy-4-morpholinoaniline in aqueous solutions: hydrolysis, trimerization, and hydroxylation processes

Beiginejad

Nematollahi

2015

Monatsh Chem

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The electrochemical oxidation of 2,5-diethoxy-4-morpholinoaniline has been studied in various pHs using cyclic voltammetry and controlled potential coulometry.The results indicate that the electrochemically generated pquinonediimine participates in different types of reactions (hydrolysis, hydroxylation, and trimerization). Instability of the produced p-quinonediimine depends on its structure, higher nucleophilicity of 2,5-diethoxy-4-morpholinoaniline, and pH of solution. In lower pH range, rate of hydrolysis is faster than hydroxylation and dimerization. In intermediate pHs rate of the dimerization is faster than hydrolysis and hydroxylation, and in the strongly alkaline solution, rate of the hydroxylation is faster than hydrolysis and dimerization. The effect of the charge of reaction site (C 1 ) and N 1 =C 1 bond order (Wiberg bond indices) on the hydrolysis rate were studied. Calculations were performed using density functional theory B3LYP level of theory and 6-311?G(p,d) basis set. Graphical abstract NH2 N O OEt EtO -2e--H+ n o b r a C e d o n A HN N O EtO OEt O OEt EtO O NH N O EtO OEt NH2 N O OEt EtO NH N O OEt EtO HO pH =1 0-13 pH =5. 3-9 -2e-EtO O O pH=1-3 -2H+ NH3 NH O OEt EtO NH2 N O OEt EtO NH N O OEt EtO HN N O EtO OEt O OEt EtO O NH N O EtO OEt NH2 NH O OEt EtO -2e--2H+ pH=4-5.2 NH N O OEt EtO OEt

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Electron Transfer Initiated Reactions: Bond Formation and Bond Dissociation

Abstract: Figure 4. (a) Background subtracted linear voltammogram and (b) variation of convolutive current with potential for p-methoxyphenyl thiocyanate (0.69 mM) in CH 3 CN/TBAF (0.1M) at V ) 20 V/s, temperature ) 20 °C.

Cited by 236 publications

References 817 publications

N-Centered Odd-Electron Ions Formation from Collision-Induced Dissociation of Electrospray Ionization Generated Even-Electron Ions: Single Electron Transfer via Ion/Neutral Complex in the Fragmentation of ProtonatedN,N′-Dibenzylpiperazines and ProtonatedN-Benzylpiperazines

N-Centered Odd-Electron Ions Formation from Collision-Induced Dissociation of Electrospray Ionization Generated Even-Electron Ions: Single Electron Transfer via Ion/Neutral Complex in the Fragmentation of ProtonatedN,N′-Dibenzylpiperazines and ProtonatedN-Benzylpiperazines

Electrochemical Reduction of 4-Iodophenyl Sulfonyl Chloride

Mechanistic study of electrochemical oxidation of 2,5-diethoxy-4-morpholinoaniline in aqueous solutions: hydrolysis, trimerization, and hydroxylation processes

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