Quantitative Line-Shape Analysis of Temperature- and Concentration-Dependent13C-NMR Spectra of6Li- and13C-Labelled Organolithium Compounds. Kinetic and Thermodynamic Data for Exchange Processes in Dibromomethyllithium, (Phenylthio)methyllithium, and Butyllithium

1985 ◽  
Vol 68 (7) ◽  
pp. 1848-1862 ◽  
Author(s):  
Josef Heinzer ◽  
Jean F. M. Oth ◽  
Dieter Seebach
Keyword(s):  
Shape Analysis ◽  
Line Shape ◽  
Thermodynamic Data ◽  
Nmr Spectra ◽  
Organolithium Compounds ◽  
Line Shape Analysis ◽  
Exchange Processes

Dynamic stereochemistry of 2,3,12,13-tetrathia- and -tetraselena[4,4]metacyclophanes

1983 ◽  
Vol 61 (7) ◽  
pp. 1598-1602 ◽  
Author(s):  
Keith R. Dixon ◽  
Reginald H. Mitchell
Keyword(s):  
Low Temperature ◽  
Shape Analysis ◽  
Line Shape ◽  
Thermodynamic Data ◽  
Nmr Spectra ◽  
Temperature Limit ◽  
Temperature Dependent ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Dynamic Stereochemistry

2,3,12,13-Tetrathia- and –tetraselena[4,4]metacyclophanes exhibit temperature dependent 1H nmr spectra in which the methylene resonances change from AB spectra in the low temperature limit to singlets at higher temperatures. Coalescence temperatures are 256 and 208 K, respectively, and a complete line-shape analysis yields [Formula: see text] and [Formula: see text]. The spectra and thermodynamic data are interpreted in terms of a mechanism involving interconversion of syn conformers with little or no involvement of the anti conformers previously assumed to dominate in this type of molecule.

Quantification of 1H NMR spectra of human cerebrospinal fluid: a protocol based on constrained total-line-shape analysis

Metabolomics ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 150-160 ◽  
Author(s):  
Niko M. Jukarainen ◽  
Samuli-Petrus Korhonen ◽  
Mikko P. Laakso ◽  
Minna A. Korolainen ◽  
Matthias Niemitz ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
1H Nmr ◽  
Shape Analysis ◽  
Line Shape ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Line Shape Analysis ◽  
Human Cerebrospinal Fluid

NMR Investigations of the Pitch Dependence of Self-diffusion in Cholesteric Liquid Crystals

1988 ◽  
Vol 43 (7) ◽  
pp. 687-692 ◽  
Author(s):  
S. Oehler ◽  
R. Stannarius ◽  
H. Schmiedel
Keyword(s):  
Activation Energy ◽  
Liquid Crystals ◽  
Shape Analysis ◽  
Line Shape ◽  
Nmr Spectra ◽  
Self Diffusion ◽  
Line Shape Analysis ◽  
Twisted Nematic ◽  
Nematic Phases ◽  
C Nmr

Abstract Self-diffusion in the isotropic and twisted nematic phases of mesogenic substances has been studied by means of 1H- and 13C-NMR.From the line shape analysis of the recorded 13C-NMR spectra we obtained the diffussion coefficient D⊥ along the helical pitch.Various concentrations of a chiral additive changed the pitch P0 of a nematic mixture of phenyl-benzoates from 4.7 μm to 7.8 μm. The measured values of D⊥ were in the range from 2.4 · 10-12 m2 s-1 to 1.9 · 10-11 m2 s-1 We found an Arrhenius behaviour with an activation energy of about 55 kJ/mole nearly independent of the pitch. The obtained data for D⊥ seem to have a lower than quadratic dependence on P0.

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