Comparison of 1H-NMR and 13C-NMR

1. COMPARISON OF 1H-NMR AND
13C-NMR
Dr. Vrushali Tambe
PES Modern College of Pharmacy
(For Ladies), Moshi

2. Sr.
No.
1H NMR 13C NMR
1.
It is study of spin changes of
proton nuclei
It is study of spin changes in
carbon nuclei.
The most abundant 12C is
not detected in NMR as I=0
2. It gives information about
number of Hydrogen’s in a
molecule and types of
hydrogen in different
chemical environment.
It gives information about
number of Carbons in a
molecule with different
chemical environment.

3. Sr.
No.
1H NMR 13C NMR
3. Natural abundance
of 1H is 99.9844 %.
Natural abundance of 13C is 1.108%.
This means there is less probability of
having 13C in a molecule. Hence, this
technique needs high amount of the
sample. Or compound with 13C should
be specially synthesized to acquire
the spectra. The technique is less
sensitive than PMR.
4. Gyromagnetic ratio
of 1H is 267.5
*106 rad⋅s−1⋅T−1
It is more sensitive
than CMR
Gyromagnetic ratio of 13C is 67.2
106 rad⋅s−1⋅T−1
It is 1/4th to that of hydrogen. Hence,
the sensitivity of the technique is less.

4. Sr.
No
1H NMR 13C NMR
5. 1H couplin with
adjacent 1H is
seen.
Coupling between 13C -1H and 13C-13C is
possible.
But due to poor abundance of 13C, the
presence of adjacent 13C is unlikely. Hence,
13C-13C coupling is not seen.
CMR spectra can be acquired by
1. 13C -1H : Complex coupled spectra, gives
information about number of Hydrogen
attached to carbon
2. Decoupled spectra: this gives unsplit
lines corresponding to number of 13C in
molecule.

5. Sr.
No
1H NMR 13C NMR
6. Chemical shift range is 0-14
ppm
Chemical shift range is 0-
240ppm
7. Continuous wave and Fourier
transform method is used
Fourier transform
technique is used due to
poor sensitivity of CMR.
8. Coupling constant range is 0-15
Hz
Coupling constant range
is 125-250 Hz
9. Chemical shift is in the range of
0-14 ppm
Chemical shift is in the
range of 0-240 ppm

6. Sr.
No
1H NMR 13C NMR
10. Solvent peak is not observed Solvent peak is observed
11. Area under peak is
considered.
Peak height is not
proportional to the number
of Hydrogens making the
signal.
Area under peak is not
considered.
Peak height is not always
proportional to the number
of carbons making the
signal.
12. TMS peak is singlet TMS peak quartet
13. Effect of substituent on
adjutants carbon atom can
varies chemical shift.
Effect of substituent on
adjutants carbon atom
cannot varies chemical shift

7. COUPLING OF CARBON WITH HYDROGEN