C8953
NMR strukturní analýza
semináˇr
Introduction to 2D NMR & Homonuclear correlation - COSY
Ondˇrej Jurˇcek
ondrej.jurcek@ceitec.muni.cz
March 27, 2017
2D NMR
Second dimension f1
� preparation period =⇒
coherence
� evolution period t1
FT
−−→ f1
� increments
� evolution of coherence
� mixing period
� transfer of encoded
magnetisation
� measurable signal
� detection of signal t2
FT
−−→ f2
acq
t1
prep
evolution
mixing
detection
t2
5t1
4t1
3t1
2t1
t1
2D NMR
2D spektrum
� FT in t1 - modulated 1D spectra
� FT in t2 - 2D spectrum
COSY
� easiest 2D experiment
� correlates H nuclei based
on 2/3J coupling
� through 2, 3, (4) bonds
� antiphase off-diagonal
crosspeak between coupled
atoms
� DQF-COSY - modification of
basic sequence, diagonal
crosspeaks in absorption
phase
acq
t1 t2
))
90 9090
P E M D
f1
f2
f1
f2
Hints for beginners
� Determination of individual spin systems - sharing off-diagonal crosspeaks
� Isolated protons - only diagonal crosspeak
� Already known rules: symmetry, diastereotopicity, most shielded/deshielded
atoms etc.
COSY : Betacyklodextrine
5.0
5.0
4.5
4.5
4.0
4.0
3.5
3.5
δ2 - 1H (ppm)
5.0 5.0
4.5 4.5
4.0 4.0
3.5 3.5
δ1-1H(ppm)
COSY : N-acetyllysine
8
8
6
6
4
4
2
2
0
0
δ2 - 1
H (ppm)
8 8
6 6
4 4
2 2
δ1-1
H(ppm)
COSY : N-acetyllysine
4
4
3
3
2
2
1
1
δ2 - 1H (ppm)
4.0 4.0
3.5 3.5
3.0 3.0
2.5 2.5
2.0 2.0
1.5 1.5
1.0 1.0
δ1-1H(ppm)
COSY : Atropine
8
8
6
6
4
4
2
2
8 8
6 6
4 4
2 2
δ1-1
H(ppm)
COSY : Atropine
5
5
4
4
3
3
2
2
1
1
5 5
4 4
3 3
2 2
δ1-1
H(ppm)
Chinin - 1D 1H
COSY - Chinin
10
10
8
8
6
6
4
4
2
2
δ2 - 1
H (ppm)
8 8
6 6
4 4
2 2
δ1-1
H(ppm)
5
10
6
9
7
8
3
2
4
N
1
O
CH3
22
11
12
OH
17
16
N
13
15
14
18
19
20
21
COSY - Chinin
10 8 6 4 2
8 8
6 6
4 4
2 2
δ1-1H(ppm)
5
10
6
9
7
8
3
2
4
N
1
O
CH3
22
11
12
OH
17
16
N
13
15
14
18
19
20
21