C8953
NMR strukturní analýza
semináˇr
Heteronuclear correlations
Jan Novotný
176003@is.muni.cz
April 6, 2022
1D 13C NMR
Polarization transfer
bigger population diffrenece of 1H nucleus is transfered via J-coupling to less
sensitive nucleus X (13C, 15N)
fundamental building block of heteronucler correlation experiments: in 2D-HX
experiment each crosspeak manifests interaction of H and X nucleus coupled
trough bonds
Task: Draw the evolution of magnetization during basic INEPT pulse
sequence. Consider C-H interacting pair.
Practical notes 1H-X HSQC
resolution of overlaps
routine experiments to control biomolecular sample
easy identification of geminal protons
indirect determination of protons bonded to NMR inactive heteroatom
heteronuclear correlation ⇒ no diagonal crosspeak, no symmetry
X decoupled during acquisition ⇒ singlet crosspeak
1H-13C HMBC + 1H-13C HSQC
H4-C4
H2-C2
H10-C10
H9-C9
H7-C7
H8-C8
H7-C9
H7-C8
H7-C10
H9-C10
H2-C7
H4-C6
H2-C6
H4-C1 H7-C1
H7-C2
H9-C1
Folic Acid: 1H 1D
N
N
N
N
O
NH2
N
H
O
O
O
–
O
–
O
NH
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
2425
Folic Acid: 13C 1D
N
N
N
N
O
NH2
N
H
O
O
O
–
O
–
O
NH
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
2425
Folic Acid: 1H-15N HMBC
8
8
6
6
4
4
2
2
δ2 - 1
H (ppm)
300 300
250 250
200 200
150 150
100 100
δ1-15
N(ppm)
N
N
N
N
O
NH2
N
H
O
O
O
–
O
–
O
NH
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
2425
Folic Acid: 1H-13C HMBC
8
8
6
6
4
4
2
2
δ2 - 1
H (ppm)
150 150
100 100
50 50
δ1-13
C(ppm)
N
N
N
N
O
NH2
N
H
O
O
O
–
O
–
O
NH
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
2425