Dimethyl- and Bis[(trimethylsilyl)methyl]cuprates Show Aggregates Higher than Dimers in Diethyl Ether:  Molecular Diffusion Studies by PFG NMR and Aggregation−Reactivity Correlations

2003 ◽  
Vol 125 (6) ◽  
pp. 1595-1601 ◽  
Author(s):  
Xiulan Xie ◽  
Carsten Auel ◽  
Wolfram Henze ◽  
Ruth M. Gschwind
Keyword(s):  
Diethyl Ether ◽  
Molecular Diffusion ◽  
Diffusion Studies ◽  
Pfg Nmr

Diffusion NMR and bicelle morphology

2011 ◽  
Vol 89 (9) ◽  
pp. 1021-1035 ◽  
Author(s):  
Peter M. Macdonald ◽  
Ronald Soong
Keyword(s):  
Lateral Diffusion ◽  
Diffusion Method ◽  
Nmr Studies ◽  
Diffusion Nmr ◽  
Magnetically Aligned Bicelles ◽  
Diffusion Studies ◽  
Membrane Bound ◽  
Nmr Diffusion ◽  
Pfg Nmr ◽  
Magnetically Aligned

This minireview focuses on diffusion NMR studies in bicelles. Following a discourse on diffusion fundamentals, and a comparative overview of fluorescence and NMR-based techniques for measuring diffusion, the pulsed field gradient (PFG) NMR diffusion method is introduced, emphasizing its specific advantages and limitations when applied to diffusion measurements in macroscopically oriented lamellar systems such as magnetically aligned bicelles. The utility of PFG NMR diffusion measurements in bicellar model membrane systems for examining lateral diffusion of membrane-bound molecular species is demonstrated, along with certain features of lateral diffusion that such studies illuminate. Further, those aspects of bicelle morphology that have been resolved using PFG NMR diffusion studies of various molecular weight soluble polymeric species are reviewed. The discussion concludes with an outline of future prospects for diffusion NMR studies in bicelles.

Diffusion studies in confined nematic liquid crystals by MAS PFG NMR

2009 ◽  
Vol 196 (2) ◽  
pp. 110-114 ◽  
Author(s):  
Ekaterina E. Romanova ◽  
Farida Grinberg ◽  
André Pampel ◽  
Jörg Kärger ◽  
Dieter Freude
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Diffusion Studies ◽  
Pfg Nmr

PFG NMR self-diffusion studies of fluid transport and surface-to-volume ratios in sands

2001 ◽  
Vol 19 (3-4) ◽  
pp. 584
Author(s):  
F. Stallmach ◽  
C. Vogt ◽  
P. Galvosas ◽  
J. Kärger ◽  
N. Klitzsch
Keyword(s):  
Fluid Transport ◽  
Self Diffusion ◽  
Diffusion Studies ◽  
Pfg Nmr

Self-diffusion studies of pore fluids in unconsolidated sediments by PFG NMR

2002 ◽  
Vol 50 (4) ◽  
pp. 455-467 ◽  
Author(s):  
Corina Vogt ◽  
Petrik Galvosas ◽  
Norbert Klitzsch ◽  
Frank Stallmach
Keyword(s):  
Unconsolidated Sediments ◽  
Pore Fluids ◽  
Self Diffusion ◽  
Diffusion Studies ◽  
Pfg Nmr

Self-Diffusion Studies in CuBTC by PFG NMR and MD Simulations

2010 ◽  
Vol 114 (23) ◽  
pp. 10527-10534 ◽  
Author(s):  
M. Wehring ◽  
J. Gascon ◽  
D. Dubbeldam ◽  
F. Kapteijn ◽  
R. Q. Snurr ◽  
...  
Keyword(s):  
Md Simulations ◽  
Self Diffusion ◽  
Diffusion Studies ◽  
Pfg Nmr

Nafion® Membranes: Molecular Diffusion, Proton Conductivity and Proton Conduction Mechanism

1992 ◽  
Vol 293 ◽  
Author(s):  
Klaus-Dieter Kreuer ◽  
Thomas Dippel ◽  
Wolfgang Meyer ◽  
Joachim Maier
Keyword(s):  
Water Content ◽  
Proton Conductivity ◽  
Molecular Diffusion ◽  
Local Environment ◽  
Bulk Water ◽  
Exponential Factor ◽  
Nmr Diffusion ◽  
The One ◽  
Low Degrees ◽  
Pfg Nmr

AbstractH-PFG-NMR diffusion and proton conductivity data for NAFION® 117 is presented as a function of temperature and water content. From this, H2O diffusion on a molecular scale is concluded to be similar to the one in bulk water. But “geometrical” restrictions of diffusion lead to a decreasing pre-exponential factor, i.e. decreasing macroscopic diffusion coefficient with decreasing water content. It is shown that proton conductivity is correlated with water diffusion for low degrees of hydration (vehicle mechanism). With increasing hydration there is an increasing contribution from “structure diffusion” culminating in an amplification factor of A = 2.5 for fully hydrated protonic NAFION® 117 at room temperature. The bonding of water in NAFION® as well as the local environment (hydration) of the acidic proton are concluded to be similar as in acidic aqueous solutions.

Relation Between Structure and Diffusion in Nanostructured Porous Solids and in Lipid Membranes

2005 ◽  
Vol 899 ◽  
Author(s):  
Sergey Vasenkov ◽  
Jörg Kärger
Keyword(s):  
Lipid Membranes ◽  
Molecular Transport ◽  
Domain Size ◽  
Porous Solids ◽  
Diffusion Studies ◽  
Lipid Diffusion ◽  
Effective Diffusivities ◽  
Pfg Nmr ◽  
Fcc Catalysts ◽  
And Diffusion

AbstractPulsed field gradient (PFG) NMR technique has been applied to study molecular transport in two different types of nanostructured materials, viz. in fluid catalytic cracking (FCC) catalysts and in lipid membranes. Diffusion studies have been performed for a broad range of molecular displacements covering displacements that are as small as a fraction of a micron. The effective diffusivities recorded on various length scales are used to evaluate the relevance of various transport modes in the particles of FCC catalysts for the rate of molecular exchange between catalyst particles and the surrounding atmosphere. This rate is shown to be primarily related to the diffusion in the meso- and macropores of the particles under the condition of fast molecular exchange between these pores and the zeolite crystals located in the particles. Studies of lipid membranes are focused on developing fundamental understanding of the influence of various types of domains on lateral mobility of lipids. A meaningful study of this influence requires an ability of monitoring lipid diffusion for different displacements that are smaller and larger than the domain size. First PFG NMR data along this direction are presented.

Sign in / Sign up

Export Citation Format

Share Document