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12.12 NMR Problems

Extra Problems

12. For each molecule, indicate the number of unique proton groups and carbon atoms on the lines provided (i.e., how many you would see in the NMR).

a)
Problem 12a, nmr problems
b)
Problem 12b, nmr problems
c)
Problem 12c, nmr problems
d)
Problem 12d, nmr problems
e)
Problem 12e, nmr problems
f)
Problem 12f, nmr problems
g)
Problem 12g, nmr problems
h)
Problem 12h, nmr problems
i)
Problem 12i, nmr problems

j) bromopropane

k) 1-bromo-1,1-dimethylethane

13. Identify the approximate chemical shifts (in ppm) of the protons in the following compounds. a) CH3CH2CHO

b) Ph-CH3

c) (CH3)3N

d) H2C=CH-Ph

e) CH3CH2CO2H

f) CH3OCH3

g) CH3CH2Br

14. Identify the chemical shift range (0-50, 50-100, 100-150, 150-200 ppm) of the carbons in the following compounds.

a) CH3CH2CHO

b)
Problem 14b, nmr problems
c)
Problem 14c, nmr problems
d)
Problem 14d, nmr problems
e)
Problem 14e, nmr problems
f)
Problem 14f, nmr problems
g)
Problem 14g, nmr problems
h)
Problem 14h, nmr problems

15. Identify the multiplicity (singlet, doublet, triplet, etc.) for each proton group in the following compounds.

a) CH3CHO

b) CH3CH2Br

c) CH3-O-CH2CH2CH3

d) (CH3)3C-CH3

e) (CH3)2CHCl

f) Br-CH2CH2-CN

g) CH3-Br

16. Sketch the 1H NMR and 13C NMR spectra for each compound. a) CH3OH

b) chloroethane

c) 1-bromopropane

d) CH3CH2OCH3

e) CH3CH2CH22CO2H

17. Listed here are 1H NMR absorption peaks for three compounds, along with empirical formula and a key IR absorption (if applicable) as well. The following, abbreviations are typically employed: s = singlet; d = doublet; t = triplet; q = quartet; m = multiplet. Please provide structures consistent with these data.

Problem 17, nmr problems (1 of 5)
Problem 17, nmr problems (2 of 5)
Problem 17, nmr problems (3 of 5)
Problem 17, nmr problems (4 of 5)
Problem 17, nmr problems (5 of 5)

18. A 1H NMR spectrum was taken of an alcohol. The sample was then shaken with D2O. Another spectrum was acquired. What does this tell you about the peak labeled with the blue arrow in the original spectrum? What is this new peak labeled with the red arrow in the second spectrum?

Problem 18, nmr problems (1 of 2)
Problem 18, nmr problems (2 of 2)

19. Match each of the following compounds with its 1H NMR spectrum.

Problem 19, nmr problems (1 of 8)
Problem 19, nmr problems (2 of 8)
Problem 19, nmr problems (3 of 8)
Problem 19, nmr problems (4 of 8)
Problem 19, nmr problems (5 of 8)

20.

a) Draw the structure of the following ester (formula C5H10O2) given its 1H and 13C NMR spectra.

Problem 19, nmr problems (6 of 8)
Problem 19, nmr problems (7 of 8)

b) Once you have identified the complete structure of this compound, fill in the lines below to complete the DEPT-45, DEPT-90, and DEPT-135 spectra. Be sure to consider all five carbon peaks.

Problem 19, nmr problems (8 of 8)

21. Draw the structure of the following compound with the formula C3H6O given its 13C NMR and DEPT spectra.

Problem 21, nmr problems

22. An ester with the formula C10H12O2 has the following NMR spectra. Draw its structure.

Problem 22, nmr problems (1 of 2)
Problem 22, nmr problems (2 of 2)

23. A compound with the formula C5H10O has the following 1H and 13C NMR spectra. Draw its structure.

Problem 23, nmr problems (1 of 2)
Problem 23, nmr problems (2 of 2)

24. A compound with an M+ of 86 in its mass spectrum has the following spectra.

Problem 24, nmr problems (1 of 3)
Problem 24, nmr problems (2 of 3)
Problem 24, nmr problems (3 of 3)