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NMR N uclear M agnetic R esonance

NMR N uclear M agnetic R esonance. Proton NMR (and other nuclei): Conformational exchange. Index. NMR-basics. H-NMR. NMR-Symmetry. Heteronuclear-NMR. Dynamic-NMR. Chemical Equivalence by Interconversion. Equivalence in Shift Depends on Temperature, Solvent, Catalyst….

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NMR N uclear M agnetic R esonance

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  1. NMRNuclear Magnetic Resonance ProtonNMR (and other nuclei): Conformational exchange Index NMR-basics H-NMR NMR-Symmetry Heteronuclear-NMR Dynamic-NMR

  2. Chemical Equivalence by Interconversion Equivalence in Shift Depends on Temperature, Solvent, Catalyst… • Keto-Enol Interconversion • Restricted Rotation (amides) • Rings InterconversionAxial H -> equatorial H Rapid at room temperature, Slow at –60C

  3. Keto-Enol Interconversion

  4. Keto-Enol Interconversion CH3 CH2 =CH =CH Keto CH2 OH enol

  5. Keto-Enol Interconversion =CH CH3 Keto CH2 enol Keto

  6. Restricted Rotation

  7. Restricted Rotation

  8. Ring Interconversion

  9. Ring Interconversion C-NMR 30oC Cis-1,4-dimethylcyclohexane -60oC

  10. Ring Interconversion

  11. Exchange : DNMR – Dynamic NMR NMR is a convenient way to study rate of reactions – provided that the lifetime of participating species are comparable to NMR time scale (10-5 s) At low temperature, hydrogens form an A2B2X spin system At higher temperature germanium hop from one C to the next

  12. Index NMR-basics H-NMR NMR-Symmetry Heteronuclear-NMR Dynamic-NMR NMR and Organometallic compounds

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