1. NMR Applications in Chemistry
Chem. Shift
J Coupling
NMR
spectrum
Structure
Peak Int.
Correlation
H-H，C-H
NOE
Applications:
• Sample quality control for Synthetic works.
• Elucidation of chemical structures.
• Getting functional group, bonding, dynamics, kinetics and chemical exchange information of molecules.
• 3D structures of the molecules.

2. Some common NMR experiments:
Connections through bonds（spin-spin coupling）
Homonuclear： 1D、2D 1H-1H COSY, DQF-COSY, TOCSY
usage：spin system assignment
Heteronuclear：
Direct (detect 13C): APT, DEPT, HETCOR
Inverse (detect1H): HMQC, HSQC, HMBC, HSQC-COSY,
HSQC-TOCSY, HMQC-TOCSY
usage：assigning heteronuclei、connecting spin systems
Connections through space（dipolar coupling）
1D、2D NOESY，ROESY, HOESY(HSQC-NOESY)
usage： connecting spin systems 、structure determination

3. 2D COSY — Homonuclear Shift COrrelation SpectroscopYAQ
The basic COSY (x=45° or 90°) pulse sequence
90° x° t2
COSY spectrum is used for determining the connectivities
between protons on the basis of geminal and vicinal couplings.
Disadvantage: bulky dispersive diagonal peaks.

4. 2D Gradient COSY-45 1 2 3 4 4
3-4
2-3 3
1-2 2 1

5. 2D DQF－COSY(Double-Quantum Filtered COSY)
90 t1 t2
allow J coupling constant measurements
observing cross-peaks close to diagonal
But lower sensitivity (~40%) of COSY expt.

6. 2D Gradient DQF-COSY

7. 3J=8.00Hz

8. TOCSY (TOtal Correlation SpectroscopY) or
HOHAHA(Homonuclear Hartman-Hahn Spectroscopy)
mixing time AQ t2 t1  
MLEV17
Pulse sequence for a TOCSY spectrum.
COSY
RL-COSY
TOCSY
Different mixing time gives different degree of relay of correlation. At small mixing time, TOCSY spectrum is similar to COSY spectrum. At long mixing time, gives total correlation.

9. 2D Gradient TOCSY, mixing time=10ms3 4 4
3-4
2-3 3
1-2 2
Same as COSY spectrum 1

10. 2D Gradient TOCSY, mixing time=20ms1 2 3 4 4
2-4
3-4
1-3
2-3 3 2
1-2
Same as RL－COSY 1

11. 2D Gradient TOCSY, mixing time=50ms1 2 3 4 4
2-4
3-4
1-4
1-3
2-3 3 2
1-2
Total Correlation 1

12. By suitable combination of
DEPT: Distortionless Enhancement by Polarization Transfer
Heteronuclear expt.
Detection: 13C
Distinguish
CH, CH2, CH3
By suitable combination of
=45, 90 & 135 spectra
CH & CH3up
CH2 down
Only CH
All CH’s

13. HETCOR (Heteronuclear chemical shift correlation, 1H - 13C COSY)AQ 1H t1 1 2
1H decoupling
Removing JCH splittings
The standard pulse sequence for 13C-detected
1H-13C chemical shift correlation.
*But Inverse experiment has the following Advantages:
•increase sensitivity of detecting the less sensitive nuclei
•1H is in the direct detection dimension => larger np => better resolution

14. Pulse sequence for 1H-detected 1H-13C
HMQC (Heteronuclear Multiple Quantum Coherence)
HSQC (Heteronuclear Single Quantum Coherence) t2 1H AQ
13C
/2
/2 t1
/2
/2
GARP-1
13C decoupling
Removing JCH splittings
Pulse sequence for 1H-detected 1H-13C
correlation through single-quantum coherence
• HSQC can give considerably better 13C resolution and sensitivity than HMQC for CH2 groups of natural products
• HMQC has simpler pulse sequence and it is more robust and easier to perform.

15. (HMQC and HETCOR spectra look similar)
HSQC spectrum: H-C correlated 1 2 3 4
H-dimension 4 3 2
C-dimension 1
(HMQC and HETCOR spectra look similar)

16. HSQC-TOCSY Pulse sequence for 1H-detected HSQC-TOCSY experiment
mixing time
SLy
SLy 1H AQ
MLEV17
13C
/2
/2 t1
/2
/2
GARP-1
Pulse sequence for 1H-detected HSQC-TOCSY experiment
through single-quantum coherence.
Longer mixing time gives longer extend of spin-spin
correlations.

17. Gradient HSQC-TOCSY(mixing time=10ms)2 3 4
H-dimension 4 3 2
1-2
C-dimension
Same as HSQC－COSY spectrum 1
1-1
2-1

18. Gradient HSQC-TOCSY(mixing time=20ms)1 2 3 4
H-dimension 4 3
1-3 2
1-2
C-dimension 1
1-1
2-1
3-1

19. Gradient HSQC-TOCSY(mixing time=80ms)1 2 3 4
H-dimension 4
1-4 3
1-3 2
1-2
C-dimension 1
1-1
2-1
3-1
4-1

20. HMBC (Heteronuclear Multiple-Bond Correlation Spectroscopy)AQ
13C
Pulse sequence for HMBC
C2, C3 and C4: Quaternary or protonated carbons X: O, N
Long range connections or connections between spin systems

21. Gradient HMBC H-dimension C-dimension 2 3 1 5 1 2 3 3-4 4 3-5 5 2-6
1-7 7 8
2-7
1-8

22. 2D NOESY (Nuclear Overhauser Enhancements SpectroscopY)AQ
The NOESY pulse sequence.
—C — ~ —C —
VC*r -6, r0.5nm Ha Hb
r0.5nm
For resonance assignment, chemical structure elucidation & 3D structure determination

23. Gradient NOESY
3-CH3, 5-H

24. assignment of peptides2 3 1 1 2 1 3 3
NOESY
gives sequential
assignment of peptides 2

25. 2D ROESY pulse program 90° t1 Spin-lock t2
mixing time t1
Spin-lock t2
For small molecule NOE can be very small or zero，ROESY can be used in place of NOESY experiment. ROE intensity is also related to the H-H distances.

26. Structure Determination Procedures
1D 1H & 13C & DEPT (+MS、IR，basic chemical structure or functional groups information）
Establish 13C-1H connections by thru bond JCH couplings
HMQC、HSQC、HSQC-TOCSY experiments
Establish 1H-1H connection (spin systems or partial pieces）
Decoupled 1H, 1D TOCSY, 2D 1H-1H COSY, TOCSY expts.
（usually starts with well-resolved 1H signals）
Long range connections（connecting spin systems & assigning quaternary carbon）
1D NOESY & 2D HMBC, NOESY, ROESY experiments
3D structure or conformation determination
1D NOESY & 2D NOESY, ROESY, (HSQC)-NOESY expts.