Nuclear Magnetic
Resonance Spectroscopy
Learning Objectives
Use high resolution n.m.r spectrum of simple molecules
(carbon, hydrogen & oxygen) to predict
The different types of proton present
The relative numbers of each type of proton
The number of protons adjacent to a given proton
Possible structures
Given a simple molecule predict features of the n.m.r
spectrum.
Describe the use of D2O to identify –OH groups
Nuclear Magnetic
Resonance Spectroscopy
Nuclear Magnetic
Resonance Spectroscopy
Nuclear Magnetic
Resonance Spectroscopy
H
Nuclear Magnetic
Resonance Spectroscopy
Nuclear Magnetic
Resonance Spectroscopy
Nuclear Magnetic
Resonance Spectroscopy
Nuclear Magnetic
Resonance Spectroscopy
Absorption peak
corresponds to the radio
frequency absorbed

Only nuclei with an odd number of
nucleons (neutrons and protons) possess
a magnetic spin
1H
(proton nmr)
13C

The vast majority of proton NMR
spectroscopy is performed on liquids.

You have a solid sample, what do you
dissolve it in?
structure
spectrum
Proton NMR Spectra
A
B
S
O
R
T
I
O
N
Electrons around the nucleus shield it
from the applied magnetic field.
Different radio-frequencies are aborbed
depending on the environment of the
proton.
CHEMICAL SHIFT is a measure of the
magnetic field experienced by protons in
different environments.
CHEMICAL SHIFT is measured in ppm
relative to TMS, Si(CH3)4
CHEMICAL SHIFT tells us about the
types of protons present
CHEMICAL SHIFT
A
ABSORPTIONS
B
The area under each peak is directly
proportional to the number of protons
responsible for the absorption
S
O
R
These areas are most often presented as
integration traces on the spectrum
T
I
O
N
CHEMICAL SHIFT
Your Turn
Our Turn
Different types of proton?
Relative numbers of each
type of proton?
CH3CH2OH
CH3CH2OH
CH3CH2OH
CH3CH2OH
CHEMICAL
SHIFT ppm
Type of
proton
Number of
protons
1.0
R-CH3
3
3.5
O-CH2-R
2
4.9
R-O-H
1
Predict
3 different types of
proton
Number protons is in
ratio 1:2:3
Assign possible types
of proton to chemical
shifts obtained
structure
CH3CH2OH
Expect 3 different
types of proton
Expect peaks in the
following ranges
0.7-1.6ppm (CH3)
3.3-4.3ppm (CH2-O)
3.5-5.5ppm (OH)
Expect integration
3:2:1
spectrum
Learning Objectives
Use high resolution n.m.r spectrum of simple molecules
(carbon, hydrogen & oxygen) to predict
The different types of proton present
The relative numbers of each type of proton
The number of protons adjacent to a given proton
Possible structures
Given a simple molecule predict features of the n.m.r
spectrum.
Describe the use of D2O to identify –OH groups
The number of absorption peaks tells us the
number of different types of protons.
The chemical shift helps us identify the type
of proton.
The integration values tells us the relative
number of protons.
Old Exam Questions
[7]
[8]