NATIONAL QUALIFICATIONS CURRICULUM SUPPORT
Chemistry
Proton (1H) NMR Spectroscopy
Learner’s Workbook
[REVISED ADVANCED HIGHER]
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Acknowledgement
The publisher gratefully acknowledges permission to use the following sources: link to video
clip from http://www.le.ac.uk/spectraschool/, 10 spectra graphs both © The Royal Society of
Chemistry’s Spectra School website; adapted diagram showing nuclei as compass needles,
diagram showing external magnetic field, image of low and high resolution spectra all © Jim
Clark http://www.chemguide.co.uk.
© Crown copyright 2012. You may re-use this information (excluding logos) free of charge in
any format or medium, under the terms of the Open Government Licence. To view this licence,
visit http://www.nationalarchives.gov.uk/doc/open-government-licence/ or e-mail:
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PROTON (1H) NMR SPECTROSCOPY (AH, CHEMISTRY)
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Contents
Proton environments
4
Assigning peaks
6
Drawing spectra
7
Analysing spectra
9
PROTON (1H) NMR SPECTROSCOPY (AH, CHEMISTRY)
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LEARNER WORKBOOK
Proton environments
For the examples below:
(a)
(b)
draw the full structural formula
circle the different proton environments.
1.
Propan-1-ol
2.
Propan-2-ol
3.
Butane
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4.
But-2-ene
5.
Methyl benzene
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Assigning peaks
Use the 1 H NMR correlation table in the data book to predict the chemical
shift of the protons in the examples in the above question.
1.
Propan-1-ol
Group
CH 3
2.
Propan-2-ol
Group
3.
Chemical shift (ppm)
Methyl benzene
Group
6
Chemical shift (ppm)
But-2-ene
Group
5.
Chemical shift (ppm)
Butane
Group
4.
Chemical shift (ppm)
1.2
Chemical shift (ppm)
PROTON (1H) NMR SPECTROSCOPY (AH, CHEMISTRY)
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LEARNER WORKBOOK
Drawing spectra
For the examples above, draw the low resolution NMR spectrum you would
expect to see. Remember to draw in the appropriate peak heights – you can
assume the peak height is the same as the area under the curve if the peak is
very narrow.
1.
Propan-1-ol
2.
Propan-2-ol
3.
Butane
PROTON (1H) NMR SPECTROSCOPY (AH, CHEMISTRY)
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4.
But-2-ene
5.
Methyl benzene
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Analysing spectra
For each of the following examples analyse the high resolution proton NMR
spectrum and suggest a structural formula for each compound.
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Example 1
C2H6O
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Example 2
C3H6O
Expanded
peak cluster
at 1.11 ppm
Expanded peak
cluster at 9.79 ppm
Expanded peak
cluster at 2.48 ppm
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Example 3
C4H8O2
Expanded peak
cluster at 4.12 ppm
Expanded
peak cluster
at 1.26 ppm
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Example 4
C5H10O2
Expanded peak
cluster at 2.32 ppm
Expanded peak
cluster at 4.13 ppm
Expanded
peak clusters
at 1.26 and
1.14 ppm
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Example 5
C5H10O
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Example 6
C7H8
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Example 7
C9H10O2
Expanded peak
cluster at 4.36 ppm
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PROTON (1H) NMR SPECTROSCOPY (AH, CHEMISTRY)
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Expanded peak
cluster at 1.37 ppm