NMR Exercises 

Introduction
The exercises below require software that is available free from Advanced Chemistry Development, Inc.  Please go to the NMR Tutorial for information concerning the programs required to view the spectra in these exercises and for instructions on how to use them.  Table 1 contains links to the 1H-NMR spectra of 29 compounds.  The spin-spin splitting patterns in all these spectra are first order. 

Directions

  • Click a link in Table 1 to download the appropriate 1H spectrum.  You may want to resize the Spectrum Window once it opens.
  • Select the Integral Curve option from the Tools menu to determine the relative numbers of each type of hydrogen atom.  You can measure the height of each integral directly from the graph. (If you have a molecular formula, calculate the index of hydrogen deficiency.  If you have an elemental analysis, calculate the empirical formula.)
  • Note the chemical shifts of each signal.  Then refer to a 1H-NMR Correlation Table to determine the electronic environment of each type of hydrogen atom in the compound.
  • Zoom in on various regions of the spectrum as necessary to see the splitting pattern of a particular signal more clearly.  You can use the Measure Distance tool to determine coupling constants.
  • Draw molecular fragments that are consistent with the splitting patterns.
  • Draw structures that contain these fragments.  Remember: -Br, -Cl, and -CN groups always occur at the end of a chain.  Carbonyl groups, O=C<, carboxyl groups, -O-C(=O)-, and -O- atoms are useful for connecting two molecular fragments.   All of these atoms and groups are invisible in 1H-NMR spectra.
  • Check that the splitting pattern expected for your structure is consistent with that in the 1H spectrum.
  • Check that your structure is consistent with the Additional Data provided in Table 1.
  • Use the JME Molecular Editor to draw the structure you have deduced.
  • Paste the SMILES for that structure into the appropriate text field and click anywhere outside the box to see if you are correct.

Table 1
1st Order Spectra

Compound

1HNMR

Additional Data

 SMILES

1

Ex1H

C(54.53%) H(9.15%)
FW = 132.16

2

Ex2H

This isomer of C4H2BrClO is not 2-bromo-3-chlorofuran.

3

Ex3H

 C(40.71%) H(5.12%) Br(45.13%)
FW = 177.04
The 3JHH value indicates the stereochemistry of this compound. 


(Specify stereochemistry)

4

Ex4H

C(80.56%) H(7.51%)
This molecule contains a plane of symmetry.

5

Ex5H

FW = 60.10

6

Ex6H

C(63.15%) H(5.30%) N(14.73%),
FW = 95.10

7

Ex7H

C9H4Cl2O

8

Ex8H

C(64.58%) H(10.84%)
FW = 130.19
Signal at 11.86 exchanges with D2O.

9

Ex9H

C(74.97%) H(8.39%)
FW = 96.13 

10

Ex10H

C(65.60%) H(9.44%)
FW = 128.17

11

Ex11H

C4H5ClO

12

Ex12H

C4H5ClO

13

Ex13H

This is a gasoline additive.

14

Ex14H

C(52.17%) H(4.38%) N(20.28%) 

15

Ex15H

The peak at 8.08 ppm exchanges with D2O.

16

Ex16H

C(89.94%) H(10.06%)

17

Ex17H

Chemists abbreviate this compound MEK.

18

Ex18H

C4H8O2

19

Ex19H

An isomer of compound 18.

20

Ex20H

This compound contains two chlorine atoms.

21

Ex21H

See problem 1.

22

Ex22H

C5H7NO

23

Ex23H

This one is too volatile to be a gasoline additive. 

24

Ex24H

This compound is related to witch hazel.

25

Ex25H

C5H10O

26

Ex26H

C5H10O2

27

Ex27H

C5H10O3

28

Ex28H

This isomer of C6H2Cl4 yields two compounds with the formula C6H2BrCl3. 

O=CHem Directory