On the nature of tetraalkylammonium ions in common electrochemical solvents: General and specific solvation – Quantitative aspects

Fry, Albert J.; Steffen, L. Kraig

doi:10.1016/j.jelechem.2009.11.011

Cited by 12 publications

(20 citation statements)

References 53 publications

(70 reference statements)

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“…Computational methods, however, have been applied to ion pairing only recently, such as in a series of studies by Fry. [12][13][14][15][16][17][18] More recently, modeling of ion pairs in electrolytes has been used to reveal the importance of such structures in the research of electrochemical energy storage. 19,20 While those studies are on species with fixed charges, here we have systematically studied a series of oligofluorenes (Fig.…”

Section: Introductionmentioning

confidence: 99%

Multiply Reduced Oligofluorenes: Their Nature and Pairing with THF-Solvated Sodium Ions

Wu¹,

Zaikowski

Kaur³

et al. 2016

J. Phys. Chem. C

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Conjugated oligofluorenes are chemically reduced up to five charges in tetrahydrofuran solvent and confirmed with clear spectroscopic evidences. Stimulated by these experimental results, we have conducted a comprehensive computational study of the electronic structure and the solvation structure of representative oligofluorene anions with a focus on the pairing between sodium ions abd these multi-anions. Using density functional theory (DFT) methods and a solvation model of both explicit solvent molecules and implicit polarizable continuum, we first elucidate the structure of tightly solvated free sodium ions, and then explore the pairing of sodium ions either in contact with reduced oligofluorenes or as solvent-separated ion pairs. Computed time-dependent-DFT absorption spectra are compared with experiments to assign the dominant ion pairing structure for each multi-anion. Computed ion pair binding energies further support our assignment. The availability of different length and reducing level of oligofluorenes enables us to investigate the effects of total charge and charge density on the binding with sodium ions, and our results suggest both factors play important roles in ion pairing for small molecules. However, as the oligofluorene size grows, its charge density determines the binding strength with the sodium ion.

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Section: Introductionmentioning

confidence: 99%

Multiply Reduced Oligofluorenes: Their Nature and Pairing with THF-Solvated Sodium Ions

Wu¹,

Zaikowski

Kaur³

et al. 2016

J. Phys. Chem. C

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“…This effect would suggest that the ferrocene can diffuse more easily inside the pinholes of the film, which would imply that a lower amount of electrolyte ions would be present inside the film because of the higher size of E 4 N + with respect to Me 4 N + . At this point, it is worth to mention that de channels of the grafted film are hydrophilic because of the presence of the nitro groups present in its inner structure, whereas the hydrophobic nature of the tetraalkylammonium cations increases with the length of its aliphatic chains . In this regard, it would be expected that the presence of tetraalkylammonium ions inside the film channels must be diminished not only by its bulky nature but also by their hydrophobic properties.…”

Section: Resultsmentioning

confidence: 99%

“…At this point, it is worth to mention that de channels of the grafted film are hydrophilic because of the presence of the nitro groups present in its inner structure, whereas the hydrophobic nature of the tetraalkylammonium cations increases with the length of its aliphatic chains. [38] In this regard, it would be expected that the presence of tetraalkylammonium ions inside the film channels must be diminished not only by its bulky nature but also by their hydrophobic properties. A more significant change was observed when the modified electrode was tested in the solution of n-Bu 4 NPF 6 ( Figure 6C), where now a peak shape for the ferrocene oxidation is observed.…”

Section: The Current Rectification Of Ferrocene As Redox Probementioning

confidence: 99%

Effect of Electrolyte Ions on the Formation, Electroactivity, and Rectification Properties of Films Obtained by Electrografting

2019

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The oxidation of 4‐(4‐nitrophenyl)butyrate ions in acetonitrile was used to modify glassy carbon surfaces with films bearing 3‐(4‐nitrophenyl)propyl groups. The main features of the voltammetric reduction of the grafted nitrophenyl groups were studied in two different supporting electrolytes; n‐Bu4NPF6 and Me4NPF6. The best response was obtained with the less bulky electrolyte, which was explained by the major capability of these ions to diffuse inside the channels of the grafted film, as well as the better stabilization of the radical anions generated during the reduction process. It was also shown that the films electrografted in presence of the bulky n‐Bu4NPF6 are thicker but less compact than those prepared in Me4NPF6. The amount of nitrophenyl groups in the grafted film that can be reduced depends on the size of the electrolyte ions. The permeation of the electrolyte ions inside the film channels determines also the voltammetric behavior of ferrocene as redox probe. A current rectification phenomenon was observed in acetonitrile solutions of bulky and hydrophobic electrolytes like n‐Bu4NPF6 and n‐Hx4NPF6, whose marginal inclusion inside the film channels promotes both the entrance of ferrocene and the expelling of ferrocenium ions from these ones. This phenomenon was emulated through a CEC mechanism in solution, where the diffusion inside the channels was described as single chemical equilibria.

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“…Ph 4 AsBPh 4 was prepared by the condensation of aqueous solutions of Ph 4 AsPh 4 B and NaBPh 4 followed by crystallization in acetonitrile as described in ref. 15. The effect of temperature was studied by shaking samples put in closed test tubes in a shaking water bath of the types "Assistant" till saturation for one week at the studied temperatures 288.15, 298.15 and 308.15 K. The solubilities were determined as explained before in ref.…”

Section: Methodsmentioning

confidence: 99%

Gibbs Free Energies, Enthalpies and Entropies of Transfer for Reference Ions Ph4 As+ and Ph4 B- in Mixed DMFA-H2O Solvents at Different Temperatures

Gomaa¹

2012

AJEE

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The thermodynamic data ( ∆ G t , ∆ H t and T ∆ S t ) of transfer for tetraphenylarsonium-tetraphenylborate (Ph 4 AsBPh 4 ) from water to mixed dimethylformamide (DMFA)-H 2 O solvents were estimated from the experimental solubility and calorimeter measurements. The experiments were done at three different temperatures 288.15, 298.15 and 308.15 K. Also the thermodynamic parameters were divided into reference anion and cation following the asymmetric deviation and their values, were discussed. Dividing all the thermodynamic functions between the cation and anion by using 1.064 factors we obtain their individual functions. The reference ion values can be easily used for evaluating the different thermodynamic parameters of any ion that contains in its counterion tetraphenyl cation or anion . By using the data given here the thermodynamic parameters for some single ion can be estimated for following their behaviour in environment. The single ion thermodynamics are helpful for predicting, explaining and mechanisms suggesting. Theoretical and engineering chemistry are in need for experimental single ion parameters for the comparison with that calculated by different solvation theories.

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On the nature of tetraalkylammonium ions in common electrochemical solvents: General and specific solvation – Quantitative aspects

Cited by 12 publications

References 53 publications

Multiply Reduced Oligofluorenes: Their Nature and Pairing with THF-Solvated Sodium Ions

Multiply Reduced Oligofluorenes: Their Nature and Pairing with THF-Solvated Sodium Ions

Effect of Electrolyte Ions on the Formation, Electroactivity, and Rectification Properties of Films Obtained by Electrografting

Gibbs Free Energies, Enthalpies and Entropies of Transfer for Reference Ions Ph<SUB>4</SUB> As<SUP>+</SUP> and Ph<SUB>4</SUB> B<SUP>-</SUP> in Mixed DMFA-H<SUB>2</SUB>O Solvents at Different Temperatures

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