scholarly journals Comment on “Boosted molecular mobility during common chemical reactions”

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. eabe8322
Author(s):  
Jan-Philipp Günther ◽  
Lucy L. Fillbrook ◽  
Thomas S. C. MacDonald ◽  
Günter Majer ◽  
William S. Price ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Reactions ◽  
Molecular Mobility ◽  
Diffusion Coefficients ◽  
Diffusion Measurement ◽  
Nmr Diffusion ◽  
Signal Intensities ◽  
Nuclear Magnetic

The apparent “boosted mobility” observed by Wang et al. (Reports, 31 July 2020, p. 537) is the result of a known artifact. When signal intensities are changing during a nuclear magnetic resonance (NMR) diffusion measurement for reasons other than diffusion, the use of monotonically increasing gradient amplitudes produces erroneous diffusion coefficients. We show that no boosted molecular mobility is observed when shuffled gradient amplitudes are applied.

scholarly journals Comment on “Boosted Molecular Mobility During Common Chemical Reactions"

2020 ◽  
Author(s):  
Jan-Philipp Günther ◽  
Lucy Fillbrook ◽  
Thomas MacDonald ◽  
Günter Majer ◽  
William S. Price ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Diffusion Coefficient ◽  
Magnetic Resonance ◽  
Chemical Reactions ◽  
Molecular Mobility ◽  
Diffusion Measurement ◽  
Nmr Diffusion ◽  
Signal Intensities ◽  
Nuclear Magnetic

The apparent “boosted mobility” observed by nuclear magnetic resonance (NMR) diffusion measurements is the result of a known artefact. When signal intensities are changing during an NMR diffusion measurement for reasons other than diffusion, the use of monotonically increasing gradient amplitudes produces erroneous diffusion coefficient values. We show that no boosted molecular mobility is observed when shuffled gradient amplitudes are applied.

scholarly journals Oxyethylated Isononylphenols in Carbon Tetrachloride

2019 ◽  
Vol 50 (12) ◽  
pp. 1381-1389
Author(s):  
Victor P. Arkhipov ◽  
Ruslan V. Arkhipov ◽  
Natalia A. Kuzina ◽  
Andrei Filippov
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Carbon Tetrachloride ◽  
Magnetic Resonance ◽  
Diffusion Coefficients ◽  
Nonionic Surfactants ◽  
Translational Diffusion ◽  
Einstein Relation ◽  
Nuclear Magnetic

Abstract Translational diffusion coefficients of ethoxylated isononylphenol molecules C9H19C6H4O(C2H4O)nH in carbon tetrachloride were measured by nuclear magnetic resonance diffusometry. The hydrodynamic radii of the molecules were determined within the framework of the Stokes–Einstein relation. We showed that ethoxylated isononylphenols in carbon tetrachloride do not form micelles, and the dependence of the diffusion coefficients and, accordingly, the hydrodynamic radii of the nonionic surfactants on the number of oxyethylene groups have a kink in the region n = 6–8.

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