Magnetic resonance in paramagnetic systems
From NMR Wiki
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The presence of an unpaired electron could have different influence on the system : | The presence of an unpaired electron could have different influence on the system : | ||
| - | [[ | + | [[Paramagnetic relaxation enhancement]] : A relaxation phenoma, that occurs with the isotope part of the electron magnetic moment |
[[Pseudocontact chemical shift]] : Change in the chemical shift due to anisotropy g factor ( the factor that tell at which frequency the electron will resonate for a given field ) | [[Pseudocontact chemical shift]] : Change in the chemical shift due to anisotropy g factor ( the factor that tell at which frequency the electron will resonate for a given field ) | ||
Revision as of 18:34, 7 August 2008
Electron magnetic moment, is around 660 time stronger as the one of the proton, so the interaction will influence much further away, that's explains the shorter relaxation observed in EPR that in NMR.
The presence of an unpaired electron could have different influence on the system :
Paramagnetic relaxation enhancement : A relaxation phenoma, that occurs with the isotope part of the electron magnetic moment
Pseudocontact chemical shift : Change in the chemical shift due to anisotropy g factor ( the factor that tell at which frequency the electron will resonate for a given field )
It's important to highlight that the g factor could vary in a very big range in comparison to chemical shift on one element. This explains why it's possible that metals induced relaxation much farther away than nitroxy ions.
Enhancing relaxation through paramagnetic molecules is a very important property that allow to make contrast agent in Magnetic resonance imagery.
