2D NMR provides more information than 1D NMR by plotting data in a space defined by two frequency axes. There are several types of 2D NMR experiments including COSY, NOESY, and HETCOR. COSY identifies spin-coupled protons by showing cross peaks between protons that are directly bonded. NOESY correlates protons that are near each other in space but not necessarily directly bonded. HETCOR plots 1H and 13C spectra on separate axes and connects carbon signals to bonded proton signals. 2D NMR techniques provide additional structural information about molecules compared to traditional 1D NMR.

1. Prepared By :
Mahendra G S
M-Pharm,Pharmaceutical Chemistry
JSSCP, MYSURU
2D NMR: Cosy,Nosy, Hector

2. Need for 2D NMR!!!

4. Need of the Hour: 2D Nuclear Magnetic
Resonance(NMR)
› The first two-dimensional experiment was proposed by Jean
Jenner.
› 2D NMR is a set of nuclear magnetic resonance spectroscopy
(NMR) methods which give data plotted in a space defined by
two frequency axes rather than one.
› 2D NMR spectra provide more information about a molecule
than one-dimensional NMR spectra.

5. › 2D NMR is Nuclear magnetic resonance spectroscopy in which
we provide a 90 degree pulse to our sample which is placed in
uniform magnetic field then we wait for (0ms-5ms)
depending upon the experiment type then again we provide
again 90 degree pulse and this time we measure signal as FID.
› As a result we get Two FID signals which are plotted with
respect to time domain.
› To get a meaningful data , we apply Fourier transform program
on FIDs to get frequency in terms of ppm.
Principle of 2D NMR

6. Stages of 2D NMR:
› Preparation: 90 degree pulse excite nuclei in sample.
› Evolution (t1): let them nuclei precision freely.
› Mixing: again 90 degree radio Frequency pulses are applied and create transverse
magnetization
› Detection (t2): observable transverse magnetization is recorded. It is usually labeled with t2

7. › Cosy- Correlation Spectroscopy
› Noesy- Nuclear Over Hauser effect Spectroscopy
› Hetcor-Heteronuclear Correlation
› Many Others like:
› Ecosy
› Roesy
› Tcosy
Types of 2D NMR

8. COSY- Correlation Spectroscopy
› COSY
The two axes now both correspond to the 1H NMR spectrum.
1H-1H COSY provides connectivity information
by allowing one to identify spin-coupled protons.
x,y-coordinates of cross peaks are spin-coupled
protons .

9.  The two-dimensional spectrum that results from the COSY
experiment shows the frequencies for a single isotope, most
commonly hydrogen (1H) along both axes.
 COSY spectra show two types of peaks:
A. Diagonal peaks
B. cross peaks

10. H-H COSY Spectrum

11. Example- Nitropropane
C NO 2
CH 3
H
CH3
doublet
septet

12. C NO
2
CH 3
H
- CH 3
- CH 3
- CH
- CH
Points on diagonal:
H’s correlated with
themselves! Not
important.

13. COSY Spectrum
Methyl Ethyl Ketone
b a
c
c
a
b

14. 1H and 13C spectra plotted separately on two
frequency axes
Coordinates of cross peak connect signal of carbon
to protons that are bonded to it.
Hetcor-Heteronuclear Spectroscopy

15. 1H-13C HETCOR
1H-NMR
13C-NMR

17. › COSY: 1H-1H correlations via spin coupling interactions, nuclei
must be closely connected by bonds.
› NOESY is a type of 2D NMR that is also a 1H-1H correlation. It
correlates nuclei that are physically near each other in space,
but not necessarily coupled to one another.
› It takes advantage of the Nuclear Overhauser Effect, recall
from our discussion of 13C NMR.
Nuclear Over Hauser effect Spectroscopy(Noesy)

24. ›Thank You for Patient
Listening !!!!!!.....