Raman scattering from p-benzoquinone

Palmö, Kim; Pietilä, Lars‐Olof; Mannfors, B.; Karonen, A.; Stenman, Folke

doi:10.1016/0022-2852(83)90093-0

Cited by 33 publications

(13 citation statements)

References 12 publications

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“…The peaks at 445, 1160, 1435, and 1663 are the typical features in the Raman spectra of BQ. 51 Thus, the observations from the flow cell studies also confirm that BQ interacts with Nafion through the sulfonate group, thereby binding BQ on the electrode surface. This increases the impedance of the BQ/BQH 2 redox reaction.…”

Section: Resultsmentioning

confidence: 58%

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Electrochemical Impedance Spectroscopy Investigation of Organic Redox Reactions (p-Benzoquinone/Hydroquinone Couple)─Implications to Organic Redox Flow Batteries

et al. 2021

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Redox reactions of organic redox couples are investigated on Nafion-free and Nafion-containing carbon (Vulcan XC-72)-modified glassy carbon disk (GCD) electrodes. The model system chosen is the p-benzoquinone (BQ)/hydroquinone (BQH 2 ) couple because BQ derivatives are common to most of the organic redox couples. The electrochemical impedance spectroscopy patterns show an unexpected rise in real resistance with time and with rotation speed (rpm). This increase in resistance is remarkable with Nafion-containing GCDs. It seems that the sulfonate group on the polymer chain attacks the redox couple to bind the species to the electrode surface. Moreover, the internal and external mass transfer features are better resolved than their nonbinding inorganic counterparts (V 4+ /V 5+ couple). These findings have enormous implications to the development of organic redox flow batteries, organic synthesis, supercapacitors, sensors, and so on.

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Section: Resultsmentioning

confidence: 58%

“…The frequencies associated with the γ(CO) mode in BQ is at ∼1660 cm –1 . The peaks at 445, 1160, 1435, and 1663 are the typical features in the Raman spectra of BQ …”

Section: Resultsmentioning

confidence: 96%

Electrochemical Impedance Spectroscopy Investigation of Organic Redox Reactions (p-Benzoquinone/Hydroquinone Couple)─Implications to Organic Redox Flow Batteries

et al. 2021

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“…Thus, the in-phase CdO stretching frequency of 1663 cm -1 for p-benzoquinone 38 is decreased by 228 cm -1 in p-benzosemiquinone radical anion and indicates that the CdO bond is substantially weaker in the radical anion. Likewise, the CdC stretching frequency of 1657 cm -1 is 37 cm -1 higher for p-benzoquinone 38 than for p-benzosemiquinone radical anion and indicates a similar weakening of the CdC bond upon reduction of p-benzoquinone. The substantial increase in the a g symmetry CCC bending mode's frequency in p-benzosemi-quinone radical anion, compared to p-benzoquinone (447 cm -1 ), 38 implies a more rigid carbon framework and indicates a more delocalized benzenoid structure for the radical anion compared to the neutral molecule.…”

Section: Radical Anions Of P-chloranil P-fluoranil and P-benzoquinonementioning

confidence: 94%

“…[54][55][56] They include the in-phase CO stretch (1435 cm -1 ), the in-phase CdC stretch (1620 cm -1 ), a CH bend (1161 cm -1 ), and a CCC bend (481 cm -1 ). Comparing measured vibrational frequencies for p-benzosemiquinone radical anion with corresponding modes for the neutral p-benzoquinone molecule 38 provides insight into changes in chemical bonding upon oneelectron reduction of p-benzoquinone, indicated in 1 and 2. Thus, the in-phase CdO stretching frequency of 1663 cm -1 for p-benzoquinone 38 is decreased by 228 cm -1 in p-benzosemiquinone radical anion and indicates that the CdO bond is substantially weaker in the radical anion.…”

Section: Radical Anions Of P-chloranil P-fluoranil and P-benzoquinonementioning

confidence: 99%

“…Comparing measured vibrational frequencies for p-benzosemiquinone radical anion with corresponding modes for the neutral p-benzoquinone molecule 38 provides insight into changes in chemical bonding upon oneelectron reduction of p-benzoquinone, indicated in 1 and 2. Thus, the in-phase CdO stretching frequency of 1663 cm -1 for p-benzoquinone 38 is decreased by 228 cm -1 in p-benzosemiquinone radical anion and indicates that the CdO bond is substantially weaker in the radical anion. Likewise, the CdC stretching frequency of 1657 cm -1 is 37 cm -1 higher for p-benzoquinone 38 than for p-benzosemiquinone radical anion and indicates a similar weakening of the CdC bond upon reduction of p-benzoquinone.…”

Section: Radical Anions Of P-chloranil P-fluoranil and P-benzoquinonementioning

confidence: 99%

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π-Donor Substituent Effects on Calculated Structures, Spin Properties, and Vibrations of Radical Anions ofp-Chloranil,p-Fluoranil, andp-Benzoquinone

Boesch

Wheeler

1997

J. Phys. Chem. A

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Vibrational and electronic properties of p-benzosemiquinone radical anions are important indicators of charge transfer in ion pairs, charge-transfer salts, and electron-transfer reactions. To provide missing data for radical anions of p-chloranil, p-fluoranil, and p-benzoquinone, and to test the capabilities of various computational methods, calculated structures, spin properties, and harmonic vibrational frequencies and mode assignments are reported based on molecular orbital, density functional, and hybrid Hartree-Fock/density functional computations. Qualitative structural changes upon reducing the neutral quinones to their semiquinone radical anions are predictable from the nodal structure of p-benzoquinone's LUMO. Furthermore, trends in calculated CO and CdC bond distance changes for the three molecules follow a pattern expected from the π-bonding abilities of the substituents. The most accurate calculated spin densities and isotropic hyperfine coupling constants show qualitative agreement with experimentally derived values for p-benzosemiquinone radical anion, whereas predicted spin densities and hyperfine coupling constants are reported for the other two species. Although calculated vibrational frequencies display small average absolute differences from experimentally measured frequencies (24 cm -1 for p-chloranil's radical anion), for p-chloranil's radical anion calculations generally fail to reproduce several important details of the vibrational spectra.

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The Essential Role of a ZnII Ion in the Disproportionation of Semiquinone Radical Anion by an Imidazolate-Bridged CuII–ZnII Model of Superoxide Dismutase

Ohtsu

Fukuzumi

2000

Angewandte Chemie

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Reduktion und Oxidation von Semichinonradikalen Q.− werden beschleunigt durch das ZnII‐Zentrum des Imidazolat‐verbrückten CuII‐ZnII‐Zweikernkomplexes [CuZn(bdpi)(CH3CN)2](ClO4)3⋅2 CH3CN 1. Die Disproportionierung von Q.− geht mit seiner koordinativen Bindung an das ZnII‐Zentrum von 1 einher; beim CuII‐CuII‐Analogon von 1 findet dagegen keine Disproportionierung von Q.− statt. Durch diese Untersuchungen lässt sich die Rolle des ZnII‐Ions in der Kupfer und Zink enthaltenden Superoxid‐Dismutase beleuchten.

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Raman scattering from p-benzoquinone

Cited by 33 publications

References 12 publications

Electrochemical Impedance Spectroscopy Investigation of Organic Redox Reactions (p-Benzoquinone/Hydroquinone Couple)─Implications to Organic Redox Flow Batteries

Electrochemical Impedance Spectroscopy Investigation of Organic Redox Reactions (p-Benzoquinone/Hydroquinone Couple)─Implications to Organic Redox Flow Batteries

π-Donor Substituent Effects on Calculated Structures, Spin Properties, and Vibrations of Radical Anions ofp-Chloranil,p-Fluoranil, andp-Benzoquinone

The Essential Role of a ZnII Ion in the Disproportionation of Semiquinone Radical Anion by an Imidazolate-Bridged CuII–ZnII Model of Superoxide Dismutase

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