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Geminal Protons (geminal + proton)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

The First Fulleropyrrolidine Derivative of Sc3N@C80: Pronounced Chemical Shift Differences of the Geminal Protons on the Pyrrolidine Ring.

CHEMINFORM, Issue 41 2005
Claudia M. Cardona
No abstract is available for this article. [source]

Reorientational dynamics of p -sulfonatocalix[4]arene and of its La(III) complex in water

MAGNETIC RESONANCE IN CHEMISTRY, Issue 7 2004
Yaël Israëli
Abstract The reorientational dynamics of p -sulfonatocalix[4]arene and of its La(III) complex in deuterated water were studied by 1H NMR longitudinal relaxation rates. It is shown that the relaxation is purely dipolar in the non-extreme narrowing regime. The distance between the geminal protons could be determined from the NMR data, giving good agreement with the values generally used in correlation time calculations. The correlation times show an Arrhenius behaviour in good agreement with previously reported data from 13C measurements for a similar uncomplexed calixarene. The Arrhenius energies of activation are identical for the uncomplexed and the complexed calixarenes, suggesting a reorientational motion strongly dependent on the structure of the water cage around the complex. This is also in agreement with a complexation of the La(III) cation in the second sphere of solvation of the sulfonate groups, as shown by molecular dynamics simulations. Copyright © 2004 John Wiley & Sons, Ltd. [source]

25R/25S stereochemistry of spirostane-type steroidal sapogenins and steroidal saponins via chemical shift of geminal protons of ring-F,

MAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2003
Pawan K. Agrawal
Abstract A method based on the differences among the 1H NMR chemical shifts of geminal protons of ring-F methylene resonances (H2 -23, H2 -24 and H2 -26) is proposed for ascertaining the 25R/25S stereochemistry of ring-F unsubstituted spirostane-type steroidal sapogenins and steroidal saponins. Copyright © 2003 John Wiley & Sons, Ltd. [source]