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Interpreting
and explaining the
H-1 NMR spectrum of dimethylamine
(N-methylmethanamine)
[Author
©
Dr Phil Brown PhD:
Doc Brown's advanced level organic chemistry exam revision notes
suitable for students of UK A level chemistry courses & US K12 grade
11, grade 12 and AP honors chemistry courses: Molecular
spectrometry - analysing the 1H NMR spectra of dimethylamine
[spectra page updated
April 3rd 2026 *]
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1H NMR spectrum of
(CH3)2NH
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H-1 proton NMR spectroscopy -
spectra index
Introductory note on the 1H NMR spectra of dimethylamine
Students and teachers please note my explanation of the
proton NMR spectrum of dimethylamine is designed for advanced, but
pre-university, chemistry courses.
The chemical shift
δ splitting pattern effects for
dimethylamine are
confined to a proton spin-spin
coupling effects analysed using the n+1 rule for adjacent
non-equivalent proton fields (n is the number of neighbouring
protons in a non-equivalent different chemical environment for the
dimethylamine molecule).
It is assumed that the integrated intensities of the
δ
chemical shifts give the ratio of the protons in the different
non-equivalent chemical environments of the dimethylamine molecule.
The most common solvent used for investigating the 1H NMR
spectrum of compounds like dimethylamine, is CDCl3 and other
deuterated solvents to avoid confusion with a 1H NMR
signal, 2D (2H) has a different chemical
shift.
TMS is the acronym for tetramethylsilane, formula Si(CH3)4,
whose protons are arbitrarily given a chemical shift of 0.0 ppm.
This is the 'standard' in 1H NMR spectroscopy and all
other proton resonances, called chemical shifts, are measured
with respect to the TMS, and depend on the
individual (electronic) chemical environment of the hydrogen atoms
in an organic molecule - dimethylamine here.
The chemical shifts quoted in ppm on the diagram of
the H-1 NMR spectrum of dimethylamine represent the peaks of the intensity of
the chemical shifts of (which are often groups of split lines at
high resolution) AND the relative integrated areas under the peaks
gives you the ratio of protons in the different chemical
environments of the dimethylamine molecule.
Dimethylamine,
N-methylmethanamine, C2H7N,
 ,
 ,
The classification,
structure and naming of
organic nitrogen compounds
Interpreting the
H-1 NMR spectrum of
dimethylamine
In terms of spin-spin coupling from the possible proton magnetic orientations,
for dimethylamine I
have only considered the interactions of
non-equivalent protons on adjacent carbon atoms
which doesn't apply here, and the N-H proton resonance is not normally split
by adjacent C-H protons and neither is the adjacent C-H resonance split by
the N-H protons, see note on resonance (b) below.
For relatively simple molecules, the low
resolution H-1 NMR spectrum of dimethylamine is a good starting point
(low resolution diagram above).
The hydrogen atoms (protons) of dimethylamine occupy
2
different chemical environments so that the low resolution NMR
spectra should show 2 principal
1H peaks of different H-1 NMR chemical shifts (diagram above for
dimethylamine).
CH3NHCH3
or (CH3)2NH
Note the
integrated proton ratio 6:1 of the 2 colours of the
7 protons of dimethylamine
in the 2 chemically different proton environments
Chemical shifts (a) to (b) on the H-1 NMR
spectrum diagram for dimethylamine.
Although there are 7 hydrogen atoms in the molecule,
there are only 2 possible different chemical
environments for the hydrogen atoms in dimethylamine molecule.
The integrated signal proton ratio 6:1 observed
in the high resolution H-1 NMR spectrum, corresponds with
the structural formula of dimethylamine.
The high resolution 1H NMR
spectrum of dimethylamine
The high resolution spectra of dimethylamine
shows 2 groups of proton resonances and in the
6:1
ratio expected from the
structural
formula of dimethylamine.
The ppm quoted on the diagram represent the peak
of resonance intensity for a particular proton group in the
molecule of dimethylamine - since the peak' is at the apex of a band of
H-1 NMR resonances due to spin - spin coupling field splitting effects - see high resolution
notes on dimethylamine below.
However, applying the
n+1 rule
to dimethylamine isn't necessary, both proton resonances
(a) 1H
Chemical shift 2.13 ppm, methyl protons: CH3NHCH3
There are no adjacent C-H protons, and
the N-H protons do not cause a splitting, so this 1H NMR
resonance shows up as a singlet in the dimethylamine
spectrum. The two methy groups are equivalent.
(b) 1H
Chemical shift ?: CH3NHCH3
The adjacent C-H protons do not cause a
splitting, so this 1H NMR resonance shows up as a
singlet in the dimethylamine spectrum.
The lack of resonance splitting is due to
exchange of protons between the amine group of the amine
molecules which inhibits the coupling between amine group
protons and any adjacent alky group protons (and vice versa) - even a trace
of water catalyses this effect.
e.g. for aliphatic primary/secondary
aliphatic amines, if R = H or alkyl
R2N-H + H-O-H
 H-R2N-H+
+ OH-
R2N-H
+ H-O-H
If deuterium oxide (D2O,
where D = 2H) is used as the NMR amine sample
solvent,
the 1H protons are rapidly replaced by
2H protons in the dimethylamine molecule.
R2N-H
+ D-O-D
R2N-D
+ D-O-H
The 2H chemical shift frequency is
different to the 1H chemical shift
frequency, so the effect of D2O is to
remove
(or reduce intensity of)
the chemical shift for the NH proton from the 1H NMR
spectrum of dimethylamine, thereby identifying the original
1H chemical shift as belonging to the
amine group N-H protons and not a C-H proton of the
dimethylamine molecule.
The splitting pattern from proton
spin-spin coupling effects is analysed using the n+1 rule for
adjacent non-equivalent proton fields (n is the number of
neighbouring protons in a non-equivalent different chemical
environment) and applied to the 1H NMR spectrum of
dimethylamine.
|
Number of directly adjacent protons 1H
causing splitting |
Splitting pattern produced from the
n+1 rule on spin-spin coupling and the theoretical ratio of line intensities |
|
0
means no splitting |
|
|
|
|
|
|
1 |
|
|
|
|
|
|
|
1
creates a doublet |
|
|
|
|
|
1 |
|
1 |
|
|
|
|
|
|
2
creates a triplet |
|
|
|
|
1 |
|
2 |
|
1 |
|
|
|
|
|
3
creates a quartet |
|
|
|
1 |
|
3 |
|
3 |
|
1 |
|
|
|
|
4
creates a quintet |
|
|
1 |
|
4 |
|
6 |
|
4 |
|
1 |
|
|
|
5
creates a sextet |
|
1 |
|
5 |
|
10 |
|
10 |
|
5 |
|
1 |
|
|
6
creates a septet |
1 |
|
6 |
|
15 |
|
20 |
|
15 |
|
6 |
|
1 |
Key words & phrases:
C2H7N
CH3NHCH3 (CH3)2NH HN(CH3)2 Interpreting the proton H-1 NMR spectra of dimethylamine, low resolution & high resolution proton
nmr spectra of dimethylamine, H-1 nmr spectrum of dimethylamine, understanding the
hydrogen-1 nmr spectrum of dimethylamine, explaining the line splitting patterns from
spin-spin coupling in the
high resolution H-1 nmr spectra of dimethylamine, revising the H-1 nmr spectrum of
dimethylamine,
proton nmr of dimethylamine, ppm chemical shifts of the H-1 nmr spectrum of
dimethylamine,
explaining and analyzing spin spin line splitting in the H-1 nmr spectrum, how
to construct the diagram of the H-1 nmr spectrum of dimethylamine, how to work out the
number of chemically different protons in the structure of the dimethylamine organic
molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR
spectrum of dimethylamine using the n+1 rule to explain the spin - spin coupling ine
splitting in the proton nmr spectrum of dimethylamine deducing the nature of the protons
from the chemical shifts ppm in the H-1 nmr spectrum of dimethylamine
examining the 1H nmr spectrum of dimethylamine analysing the 1-H nmr spectrum of
dimethylamine
how do you sketch and interpret the H-1 NMR spectrum of dimethylamine
interpreting interpretation of the 1H proton spin-spin coupling causing line
splitting in the NMR spectrum of dimethylamine
assignment of chemical shifts in the
proton 1H NMR spectrum of dimethylamine formula explaining spin-spin coupling
for line splitting for dimethylamine
secondary aliphatic amine functional group N-methylmethanamine N-methylmethylamine
How do you interpret the H-1 NMR spectrum of
dimethylamine How to interpret
the H-1 NMR spectrum of dimethylamine Explanatory diagram of the chemical
shifts of the 1H H-1 proton NMR spectrum of the dimethylamine
molecule in terms of its molecular structure. Listing data of all the chemical shift peaks in ppm in the
proton NMR spectrum of dimethylamine. How to explain the H-1 NMR spectrum of
dimethylamine. The chemical shifts and integrated values of the proton ratios in the 1-H NMR
spectrum of the dimethylamine molecule. How to work out the molecular
structure of the dimethylamine molecule from its proton NMR spectrum. The uses
and distinctive features of the proton NMR spectrum of the
dimethylamine
molecule explained. What does the H-1 proton NMR spectrum chemical
shifts tell us about the
structure and properties of the dimethylamine
molecule? explaining the spin-spin proton coupling effects in the 1H
NMR spectrum of dimethylamine. interpretation
diagram explaining the proton splitting pattern produced from the
n+1 rule and the theoretical ratio of chemical shift
δ and values of
intensities for the proton NMR spectrum lines of dimethylamine
Links associated
with
dimethylamine
The chemistry of ORGANIC NITROGEN COMPOUNDS revision notes INDEX
H-1 proton NMR spectroscopy index
(Please
read 8 points at the top of the 1H NMR index page)
The infrared
spectrum of dimethylamine
The mass spectrum of dimethylamine
The 13C carbon-13 NMR spectrum of
dimethylamine
ALL SPECTROSCOPY INDEXES
All Advanced Organic
Chemistry Notes
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