1. 2D NMR

3. Two dimensional FT yields the 2D spectrum with two frequency axes
Two dimensional FT yields the 2D spectrum with two frequency axes. If the spectrum is homonuclear (signals of the same isotope (usually 1H) are detected during the two evolution periods) it has a characteristic topology:

4. 2D NMR: COSY
Ethyl benzene is plotted on each of the two axes. Note that the diagonal within the box is also the spectrum for ethyl benzene as seen from "above.“
Off-diagonal peaks denote splitting between protons on adjacent carbons.
Note the coupling of the methyl protons at 1.1 ppm to the methylene protons at 2.8 ppm. The aromatic multiplet at 7.2 ppm is coupled with itself. Also note that neither the methyl or methylene protons are coupled to the aromatic protons at 7.2 ppm.

5. Spectrum of Ethyl Benzene

6. 2D-NMR Spectra
In two dimensional experiments, both the x and the y axes have chemical shift scales and the 2D spectra are plotted as a grid like a map.
Information is obtained from the spectra by looking at the peaks in the grid and matching them to the x and y axes.

7. COSY - Correlation Spectroscopy
both axes correspond to the proton nmr spectra.
the COSY spectra indicates which H atoms are coupling with each other.
HETCOR- Heteronuclear Correlation Spectroscopy
proton nmr spectra on one axis and the 13C nmr spectra on the other.
the HETCOR spectra matches the H to the appropriate C.

8. COSY spectra
The information on the H that are coupling with each other is obtained by looking at the peaks inside the grid.  These peaks are usually shown in a contour type format, like height intervals on a map.
In order to see where this information comes from, let's consider an example shown below, the COSY of ethyl 2-butenoate 
First look at the peak marked A in the top left corner.  This peak indicates a coupling interaction between the H at 6.9 ppm and the H at 1.8 ppm.  This corresponds to the coupling of the CH3 group and the adjacent H on the alkene.

9. COSY spectra
Similarly, the peak marked B indicates a coupling interaction between the H at 4.15 ppm and the H at 1.25 ppm.  This corresponds to the coupling of the CH2 and the CH3 in the ethyl group.
Notice that there are a second set of equivalent peaks, also marked A and Bon the other side of the diagonal.

10. COSY spectra

11. HETCOR spectra
The information on how the H are C are matched is obtained by looking at the peaks inside the grid.  Again, these peaks are usually shown in a contour type format, like height intervals on a map.
In order to see where this information comes from, let's consider an example shown below, the HETCOR of ethyl 2-butenoate.
First look at the peak marked A near the middle of the grid.  This peak indicates that the H at 4.1 ppm is attached to the C at 60 ppm.  This corresponds to the -OCH2- group.

12. HETCOR spectra
Similarly, the peak marked B towards the top right in the grid indicates that the H at 1.85 ppm is attached to the C at17 ppm.  Since the H is a singlet, we know that this corresponds to the CH3- group attached to the carbonyl in the acid part of the ester and not the CH3- group attached to the -CH2- in the alcohol part of the ester.
Notice that the carbonyl group from the ester has no "match" since it has no H attached in this example.

13. HETCOR spectra

14. 2D COSY spectrum of ethylbenzene

15. 13C DEPT
This DEPT experiment (Distortionless Enhancement by Polarization Transfer) is an example of a carbon-editing pulse sequence.
Systematic changes in the internal delays in the complex pulse program make different carbons respond in different fashions, based upon the number of protons attached.

16. HMC13CDEPT45 of Ethyl Benzene
The DEPT 45 experiment yields a positive peak for every carbon with attached protons: Ca at 16 ppm, Cb at 29 ppm, and Cd, Ce, and Cf at 128.5, 128.9, and 129 ppm, respectively.
Note in the spectrum below that carbon in the CDCl3 solvent does not give a signal, since it has no attached protons

17. HMC13CDEPT45

18. HMC13CDEPT90
In this variant of the DEPT experiment, only CH yields peaks; CH0, CH2, and CH3 are invisible.
In our example we see only three lines due to Cd, Ce, and Cf in the aromatic range from 126 to 129 ppm.

19. HMC13CDEPT90

20. HMC13CDEPT135
In this variant of the DEPT experiment, CH2 yields negative peaks, whereas CH and CH3 are positive
Thus, we see Ca, Cd, Ce, and Cf as positive peaks, while Cb is negative

21. Thank you