C8953 NMR strukturní analýza seminář
NOESY
Jan Novotný
176003@is.muni.cz
March 29, 2022
NAD+:TOCSY (40ms)
82 - 1H (ppm)
NAD+: TOCSY (40ms), detail of aromatics
9.0 8.5 82 - 1H (ppm)
NAD+: DQF-COSY, detail of aromatics
NAD+: TOCSY (40ms), detail of aliphatics
6.5
4.5-
E 5.0-
Cl
CL
5.5-
6.0-
6.5
6.0
6.0
5.5
5.0
5.5 5.0 52 - 1H (ppm)
4.0
■4.5
0-Nic
4
5 ^^3.
*NH2
8
o       31I2'
■5.0
OH OH
10
NH2
Ade 0=P-0
L O
ľ     c    16
■5.5
4'
97 N
ľ
3| |2-OH OH
■6.0
0 »
4.5
4.0
□ ť3? - =
NOESY - introduction
Nuclear Overhauser effect
► dipol-dipol interaction
► magnetisation transfer TROUGH SPACE as a consequence of cross-relaxation
NOESY
► correlates nuclei if their distance is smaller than 5 A
dAIa dt
= ~Pl(Iz ~
-s
vis = W2-W0 90 90 90
tl       ■ tmix ■ t2
acq
NOE vs. size of a molecule
NOE enhancement
Mf-Moi ^
'is _
-_Hfe-wb     where Ms is
Moi    ~ pi ~ + '
magnetisation of I perturbed by saturation
of S
Correlation time rc
► cc;0tc < 1 <a> u0j < 1 <a> u0 < f (small molecules < 1 kDa)
► fast molecular motion, /3/3 —> aa
dominates     W2 > W0 positive NOE
crosspeaks have opposite phase relative to diagonal
^orc > 1 (large molecules > 1 kDa)
► slow molecular motion, a/3 —> /3a
dominates     W0 > W2
► negative NOE
► crosspeaks have the same phase
uoqtc « 1 (cca 1 kDa)
► NOE^O - no crosspeaks
► ROESY is an alternative
►
►
dAJa dt
NOE
= ~Pl(Iz -
vis = W2-W0
NOE
w2-wD
w0 + 2^ + w2
0.5
-0.5
NOE
Application of NOESY
Mixing time rmjX
► small molecules rm\x « 500 - 800 ms
► biomolecules rmix « 50 — 300 ms
approximative determination of interatomic distatces (< 5 A)
► at short rmix
► TiiX Iji
0.2        0.4        0.6        0.8 1
mix
□ [S1
NOE differential experiment
PROBLEM 4
NOE- Difference Spectroscopy
Figure 4.1 shows the *H NMR and a 'H NOE difference spectrum of a 3-indoiylacetic acid derivative 13 bearing a methoxy group at the benzenoic ring.
9
(400 MHz iH)
Fig. 4.1. 400 MHz 'H NMR spectrum of 13 in a mixture of CDC1, and CD3OD. a Full spectrum, b expanded section of the aromatic proton signals; c 'H NOE difference spectrum, same section as in b, irradiation position at 8 = 3.64.
NOESY - Palmatine
m
CD
1.000
1.125
b
ro
m w m
z
m
CD
CO Ol
1.060 0.978
D
ro
O
b
G) (O
G) CO
OJ O)
b)
a> in
V.
Ca) O
1.111 -o
*— "D
3
3.482
4.244
0.932 3.682
ro
In
CO
ro b
2.340
Q]
Ol
3.518
"O "O
3
P
9
NOESY - Eserine in DMSO
11
—st-
4*
I-
H 13 M 14 O
H3C'V
O
82 - -"-H (ppm)
9UU9S3 - AS30N
Colchicine - DQF-COSY
6 4 82 - 1H (ppm)
Colchicine - NOESY
E
Q. Q.
to
6 4 ô2 - 1H (ppm)