2. Inside the NMR Spectrometer

3. Normal nuclei
Nuclei in a magnetic field
Radio waves will ‘pulse’ these nuclei to stimulate a response that can be recorded

4. The nuclei’s response to the ‘pulse’ is then recorded as a peak (or set of peaks) which will be placed on a graph (see above).
These peaks are always reference to TMS (tetramethylsilane = 0 ppm)
Where the peaks occur depends on the shielding or deshielding effects experience by that nuclei.

5. Approximate ppm of certain H’s (Note: Additional deshielding can change these values)

6. Very Shielded
Very deshielded
Note: Remember these values will change if there is additional deshielding effects.

7. N + 1 Rule N = N + 1 = 1 peak N + 1 = 2 N + 1 = 3 N + 1 = 4 N + 1 = 5

8. Example #1

9. Example #2 – Integration
2 cm
6 cm
2/2 = 1 equiv H’s
1 x 3 = 3 H’s
6/2 = 3 equiv H’s
3 x 3 = 9 H’s
-Divide by 2, because it is the lowest out of all the distances
-You may need to multiply by some whole number until you reach the appropriate amounts of H’s (Fudge Factor).

10. We can also use 13C NMR
*Approximate range (ppm) of different carbons

13. Time = 5 minutes of scanning
Time = 1 hour of scanning (or more)

14. Be sure to follow this example in the workshop!
Pieces of the Puzzle
# of Unsaturations =
#C - #H/2 - #Hal/2 + #N/2 +1
C = Carbon
H = Hydrogen
Hal = Halogens
N = Nitrogen
Be sure to follow this example in the workshop!

16. J Value Examples