Determination of the distance between paramagnetic centers from ESR spectra at L, S and X bands. Copper(II) in Nafion ionomers

Alonso-Amigo, M. G.; Schlick, Shulamith

doi:10.1021/ma00196a015

Cited by 12 publications

(2 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nafion membranes swollen by water and neutralized by 1% Cu2+ are similar to micelles with w = 15 in terms of sulfonic group content. 15 The dimension of the water pool is «40 A, measured form ESR data;22 this value is in agreement with scattering results. 3 The higher rc values in large micelles, compared to those in Nafion, are puzzling but in line with other studies.…”

Section: Discussionsupporting

confidence: 78%

ESR spectroscopy of AOT reverse micelles: location of cation guests and comparison with perfluorinated ionomers

Lossia¹,

Flore²,

Nimmala³

et al. 1992

J. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

7) Sharkov, A. V.; Pakulev, A. V.; Chekalin, S. V.; Matveetz, Y. A. (8) Polland, H. J.; Franz, M. A.; Zinth, W.; Kaiser, W.; Kolling, E.; (9) Petrich, J. W.; Breton, J.; Martin, J. L.; Antonetti, A. Chem. Phys. (10) Dobler, J.; Zinth, W.; Kaiser, W.; Oesterhelt, D. Chem. Phys. Letr. (11) Mathies, R. A.; Brito Cruz, C. H.; Pollard, W. T.; Shank, C. V. (12) Atkinson, G. H.; Brack, T. L.; Blanchard, D.; Rumbles, G. Chem. (13) van den Berg, R.; Jang, D.-J.; Bitting, H. C.; El-Sayed, M. A. Bio-(14) b i g , S. J.; Reid, P. J.; Mathies, R. A. J. Phys. Chem. 1991,95,6372. (15) Polland, H.-J.; Franz, M. A.; Zinth, W.; Kaiser, W.; Hegemann, P.; Biochim. Biophys. Acta 1985,808, 94. (16) Blanck, A,: Oesterhelt. D. EMBOJ. 1987. 6. 265. (17) Kandori, H.; Yoshihara, K.; Tomioka, H.; Sisabe, H. Chem. Phys. 118) Tomioka. H.: Takahashi. T.; Kamo, N.; Kobatake, Y. Biochim. Leu. 1991, 187, 579. Biophys. Acta 1686, 884, 578. 17016. for publication. (19) Duschl, A.; McCloskey, M. A.; Lanyi, J. J . B i d . Chem. 1988, 263, (20) Kandori, H.; Kemnitz, K.; Yoshihara, K. J. Phys. Chem., submitted (21) Kandori, H.; Shichida, Y.; Yoshizawa, T. Biophys. J . 1989,515,453. (22) Metzler, D. E.; Harris, C. M. Vision Res. 1978, 18, 1417. (23) Birge, R. R.; Einterz, C. M.; Knapp, H. M.; Murray, L. P. Biophys. (24) Steiner, M.; Oesterhelt, D. EMBO J. 1982, 2, 1379. (25) Tittor, J.; Oesterhelt, D.; Maurer, R.; Desel, H.; Uhl, R. Biophys. J. (26) Oesterhelt, D.; Hegemann, P.; Tittor, J. EMBOThe objective of the present study was to assess to what extent reverse micelles (RM) based on sodium bis(2-ethyl-1-hexyl) sulfosuccinate (AOT)/water/kooctane mimic locations of cations and dynamical processes in perfluorinated ionomers containing pendant sulfonic acid groups (PFSA). ESR spectra of Cuz+ and V02+ in the reverse micelles were measured at 120 and 300 K, respectively, and compared with results obtained in the ionomers. The location of cations in RM depends on the water content, expressed as w = [water]/[AOT]. The radius of the water pool is obtained from w, using r = 1 . 5~. For w = 2 ESR spectra of Cut+ indicate ligation to the sulfonic groups of the surfactant. For w in the range 5-20 the cation appears to be located both near the sulfonic groups (site 1) and in a water environment (site 2). Reverse micelles with large water content corresponding to a water pool diameter of =90 A, and swollen PFSA with water pools of -40 A, stabilize the same Cu2+ site. In both systems the cations are in a water environment, site 2. The existence of two cation sites in the intermediate w range, and the larger water pool size in RM that stabilizes the cupric cation in a water environment only, suggest a broad distribution of micelle sizes for a given w value. The dynamical properties of the cations in the same environment, based on the rotational correlation time T~ of VOz+ at 300 K, are different, most likely because of the connectivity of the water pools in the ionomers and the existence of separated droplets in the RM, even at high values of w.

show abstract

Section: Discussionsupporting

confidence: 78%

ESR spectroscopy of AOT reverse micelles: location of cation guests and comparison with perfluorinated ionomers

Lossia¹,

Flore²,

Nimmala³

et al. 1992

J. Phys. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…EPR is a technique that can be used to observe species with unpaired electrons, which the V(IV) in VO 2+ has. EPR is sensitive to the motions of detectible species, which makes it a useful tool for energy research where species mobility is important [16][17][18][19][20]. Rotational diffusion and translational diffusion can be related via the Stokes-Einstein and the Stokes-Einstein-Debye equations.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions

et al. 2018

View full text Add to dashboard Cite

The effects of sulfuric acid concentration in VO2+ solutions were investigated via electrochemical methods and electron paramagnetic resonance. The viscosity of solutions containing 0.01 M VOSO4 in 0.1–7.0 M H2SO4 was measured. Diffusion coefficients were independently measured via electrochemical methods and electron paramagnetic resonance (EPR), with excellent agreement between the techniques employed and literature values. Analysis of cyclic voltammograms suggest the oxidation of VO2+ to VO2+ is quasi-reversible at high H2SO4 concentrations (>5 mol/L), and approaching irreversible at lower H2SO4 concentrations. Further analysis reveals a likely electrochemical/chemical (EC) mechanism where the H2SO4 facilitates the electrochemical step but hinders the chemical step. Fundamental insights of VO2+/H2SO4 solutions can lead to a more comprehensive understanding of the concentration effects in electrolyte solutions.

show abstract

Multifrequency ESR of Copper Biophysical Applications

Basosi

Antholine

Hyde

1993

EMR of Paramagnetic Molecules

View full text Add to dashboard Cite

Determination of the distance between paramagnetic centers from ESR spectra at L, S and X bands. Copper(II) in Nafion ionomers

Cited by 12 publications

References 7 publications

ESR spectroscopy of AOT reverse micelles: location of cation guests and comparison with perfluorinated ionomers

ESR spectroscopy of AOT reverse micelles: location of cation guests and comparison with perfluorinated ionomers

The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions

Multifrequency ESR of Copper Biophysical Applications

Contact Info

Product

Resources

About