1. δ in ppm J in Hz 2 dimensional J resolved
Displays the Chemical shift on one dimension & the coupling pattern for that line on the othjer dimension. Overlapping multiplets become visible better for analysis
2 dimensional J resolved
1/15/2019
DR. S. Aravamudhan

2. CROSS PEAK/off diagonal peak
AX System
2 dimensional COSY
CROSS PEAK/off diagonal peak
CROSS PEAK/off diagonal peak
1/15/2019
DR. S. Aravamudhan

3. THE CROSS PEAKS ARE POSSIBLE ONLY IF THERE IS A J-COUPLING BETWEEN THE NUCLEI.
How does the J-coupling enable a certain pulse sequence to cause cross peaks where as the same pulse scheme may not have such a con sequence.
This is attributed to the aditional coherences generated when the j-couplings are non vanishing.
What are coherences and what kind of additional coherences t5aht are produced in presence of a spin spin coupling?
1/15/2019
DR. S. Aravamudhan

4. β
Nupper
-1/2
Magnetization due to the population difference
+1/2 α
Nlowe
Nlower - Nupper = ‘n’
Magnetic
field β α
No populations only coherence
When magnetization has been flipped to xy-plane
Equal occupancy
α + iβ &
α - iβ
Δm = ± 1
First order
1/15/2019
DR. S. Aravamudhan

5. Causes zero order and second order coherences
Mixing of
αβ with βα
Causes zero order and second order coherences
Thus such multiple order coherences are possible when a second π/2 pulse is applied after the preparation
1/15/2019
DR. S. Aravamudhan

6. (heteronuclear single quantum correlation)
The HSQC Experiment:
(heteronuclear single quantum correlation)
1/15/2019
DR. S. Aravamudhan

7. 1/15/2019
DR. S. Aravamudhan

8. 1/15/2019
DR. S. Aravamudhan

9. COSY DQF-COSY RCT NOESY τp t1 tM t2 Preparation Evoloution Mixing
90°
90°
COSY
DQF-COSY
RCT
NOESY τp t1 tM t2
Preparation
Evoloution
Mixing
Detection
1/15/2019
DR. S. Aravamudhan