Probing Exchangeable Protons in a Nafion Film using Thiazine Dyes

Keyword(s):  
RSC Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 6764-6765
Author(s):  
Tatyana Reshetenko ◽  
Andrei Kulikovsky

Correction for ‘Nafion film transport properties in a low-Pt PEM fuel cell: impedance spectroscopy study’ by Tatyana Reshetenko et al., RSC Adv., 2019, 9, 38797–38806, DOI: 10.1039/C9RA07794D.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 400
Author(s):  
Hajime Kamebuchi ◽  
Satoshi Tamaki ◽  
Atsushi Okazawa ◽  
Norimichi Kojima

The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2′-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s−1 and knr = 7.03 × 105 s−1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent “off-on-off” emission behavior.


Author(s):  
Anton S. Simonov ◽  
Elena P. Kharitonova ◽  
Daniil A. Fedosov ◽  
Boris A. Kolozhvari ◽  
Marat O. Gallyamov

ChemInform ◽  
1988 ◽  
Vol 19 (51) ◽  
Author(s):  
D. R. LAWSON ◽  
L. D. WHITELEY ◽  
C. R. MARTIN ◽  
M. N. SZENTIRMAY ◽  
J. I. SONG

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Amitabha Chakraborty ◽  
Shamsuzzaman Ahamed ◽  
Subrata Pal ◽  
Swapan K. Saha

Electrochemical behavior of five progressively alkylated thiazine dyes has been investigated at glassy carbon/montmorillonite and glassy carbon/zeolite electrodes. Quantitative characteristics, associated with the positions of peak potentials (Ea and Ec) and current ratios (ia/ic), are measured with scan rates. The peak current observed in the modified electrodes is dependent on both the porosity and nature and number of sites involved in partitioning the complex into film. The values of diffusion coefficient for different dyes have been calculated from electrochemical data. It is suggested that in clay-modified electrode along with physical diffusion the process of electron hopping seems to be most likely.


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