Nuclear Overhauser Effect

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Nuclear Overhauser Effect
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Nuclear Overhauser Effect (NOE)

• A change in the integrated NMR absorption
  intensity of a nuclear spin when the NMR
  absorption of another spin is saturated.

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Nuclear Overhauser Effect
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Macromolecules or in viscous solution W0
dominant, negative NOE at i due to s Small
molecules in non-viscous solution W2 dominant,
positive NOE at i due to s
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Nuclear Overhauser EffectBrownian motion and NOE
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When 1/tc gtgtw0 (or tc2 w02 ltlt1 ) extreme
narrowing limit
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When 1/tc gtgt w0 (or tc2 w02 ltlt1 ) extreme
narrowing limit
For homo-nuclear hmax 0.5 For
hetro-nuclear hmax 0.5 (gs/gi)
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• When 1/tc w0 (or tc w0 1 ) M.W. 103
• W2 and W0 effect are balanced. ? max 0
• improvement
• Change solvent ofr temperature
• Using rotating frame NOE

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When 1/tc lt w0 (or tc w0 gtgt 1 ) M.W. gt 104 W0
dominant , ? max -1 application Useful
technique for assigning NMR spectra of protein
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Nuclear Overhauser Effect distance
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citraconic acid
mesaconic acid
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