2. DEFINTION The study of the interaction between magnetic field of the nuclei and the magnetic component of the electromagnetic radiation(EMR) in the radio frequency region(RF). IR → functional group of the compound(Radio freq. → low energy → flipping of he proton ) NMR → type of proton in the structure.

3. In the presence of an external magnetic field (B 0 ), two spin states exist, +1/2 and -1/2. The magnetic moment of the lower energy +1/2 state is aligned with the external field, but that of the higher energy -1/2 spin state is opposed to the external field. Note that the arrow representing the external field points North

4. ( 10⁶ ) ( 10⁶+10)

5. What the atom used in NMR: Atoms with odd number of atomic no. or mass no. Or both. I : spin quantum no. = 0, 1⁄2, 2⁄2, 3⁄ 2. I = 0 → NO magnetic field. I = ↑ more complex the magnetic component of the nucleolus. 2

6. Why should the proton nuclei in different compounds behave differently in the NMR experiment ? The answer to this question lies with the electron(s) surrounding the proton, Since electrons are charged particles, they move in response to the external magnetic field so as to generate a secondary field that opposes the much stronger applied field. This secondary field shields the nucleus from the applied field.

7. Low Field High Field Region region

8. In the previous diagram, those compounds that give resonance signals at the higher field side of the diagram (Cl, Br,I,O,F,N) have proton nuclei that are more shielded than those on the lower field (left) side of the diagram. 1- shielded ( covered ) 2- de shielded ( not covered ) shielded need more energy to be de shielded

9. Instrument

10. Types of instrument: 1- constant RF and changeable magnetic field ranging from 0- 1400 Gouse. ex. : CH3CH2OH H in each group is different, So it need different kind of energy. 2- constant magnetic field with changeable RF. ( most common type )

11. Sample should be in a liquid state to be poured into a sample tube and examined in a NMR spectrometer. In order to take the NMR spectra of a solid, it is usually necessary to dissolve it in a suitable solvent containing no protons.

12. Solvents used: Deuterium labeled compounds, such as deuterium oxide (D 2 O), chloroform-d (DCCl 3 ), benzene-d 6 (C 6 D 6 ), acetone-d 6 (CD 3 COCD 3 ) and DMSO-d 6 (CD 3 SOCD 3 ) are now widely used as NMR solvents.

13. reference A reference standard should be used in order to locate the NMR signals TMS is used : CH3 CH3 S CH3 CH3

14. Why we choose TMS ? TMS 1- inert 2- 12 equal proton. 3- highly shielded. 4- soluble in most solvents

15. Types of instrument: low resolution splitting doesn't takes place high resolution splitting takes place.

16. What to get from the chart: 1- no. of peaks 2- chemical shift 3- integration. 4- spine- spine splitting :

17. 1-no. of peaks: Types of proton equivalentCH3CH3 Non- equivalent CH3-0-CH2CH3

18. 2-Chemical shifting: is affected by 1- electro negativity : CL CL CL C C CL CL C CL 2-distance : CH2-CL on bonds CH3-CH2-CL two bonds CH3-CH2-CH2-CL three bonds ↑ no. of bonds separating effect is less.

19. It’s measured by ppm (δ) or (τ). δ= 10-τ. ppm =shift in HTZ/spectrometer freq. MTZ EX: at 60 MTZ( CH3BR) has a shift near 162 HTZ what is the chemical shift in ppm?

20. Chemical shift for: Benzene = 7.2 ( least de shielded) Aldehyde = 9-10 ( less de shielded) Acid =10-12 ( most de shielded) N.B : NH and OH are highly exchangable.

21. 3-integration: no of H AUP (area under the peak α no. of protons)

22. 4-Spin-spin splitting: Nuclei separated by three or fewer bonds will usually be spin-coupled and will show mutual spin-splitting of the resonance signals. The splitting pattern of a given can be predicted by the n+1 rule, where n is the number of neighboring spin- coupled nuclei. If there are 2 neighboring, spin- coupled, nuclei the observed signal is a triplet ( 2+1=3 ); if there are three spin-coupled neighbors the signal is a quartet ( 3+1=4 )

23. Spin-spin splitting:

24. Example:

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