C8953
NMR structural analysis - seminar
1D 13C-NMR Jan Novotny
17 60 03@mail.muni.cz
March 1, 2022
1Hvs13CNMR
H 13C
Spin number	1H:s=| x 2H:s=1	13C:s=l x 12C:s=0
Abundance [%]	99.98	1.1
Gyromagnetic ratio [107 rad.T~1.s~1]	26.8	6.7
Chemical shift range [ppm]	0-15	0-200
Nuclear shielding		<3"dia + fpara
Integration of signals		X
7i relaxation [s]	1-20	1-40
Homonuclear J-interaction		X
H^C J-interaction (~ 100-250 Hz)	carbon satellites	(n+ 1) splitting x decoupling
vs 13C NMR
	1H	13C
Spin number	1H:s=| x 2H:s=1	13C:s=l x 12C:s=0
Abundance [%]	99.98	1.1
Gyromagnetic ratio [107 rad.T~1.s~1]	26.8	6.7
Chemical shift range [ppm]	0-15	0-200
Nuclear shielding		<3"dia + fpara
Integration of signals	/	X
7i relaxation [s]	1-20	1-40
Homonuclear J-interaction	/	X
H^C J-interaction (~ 100-250 Hz)	carbon satellites	(n+ 1) splitting x decoupling
1D 1H NMR
1D 13C NMR
U)c+0.51JHc
Wr-0.51J
HC
JUkJ
H-13Ca
1H-13Cp
1Ha-13C
1Hp-13C
12,
1H decoupled
Important regions of 13C chemical shifts
i
Aldehydes RCH=
0
R2C—CH2
Ketones R1R2C=0 I-1
RHC=CHR h
J_
i—
C-l
Alkenes R2C=CH2|-1
Aromatics
Heteroaromatics
Carboxylic acids R-C02H I-1
Esters R-C02R' I-1
C-Br
H
C-NO,
C-H Saturated Hydrocarbons
C-NH;
H
H h
C-OH
C-SR
I RC=N ! C-OR |
^Ar^
C-S02R r-C=C I--H UU U I
Amines R-CONR2 I-1
Alkynes C=CR I- h
H C-CO R
200
150
100
ppm(5)
50
0.0
1 JCh depends on the bond order ( hybridization <^> s-character)
► -C-H 1JCH ~ 125 Hz
► =C-H 1JCH ~ 160 Hz
► =C-H 1 JCh ~ 250 Hz
► X-C-H
► X = N,0, S, F,CI, ...1JCh^
► X = Li, Mg, ...1JCH^
2 JCh < 0 or close to zero (<3 Hz)
► often not observable
in 1D 13C H-C interaction suppressed by DECOUPLING simplification of spectra (splitting removed, sensitivity)
► saturation of1H energy levels during decoupling enhances relatively intensity of 13C signals because of heteronuclear nOe    quaternary carbons usually less intensive.
How many 13C signal would you expect in the NMR spectrum?
H
N
CI
N
Ru
N
CI
CI
S
CH3
C-NMR 1, bottom without CPD
13C-NMR2
2 3
H2N
y/ \W/
CI
H
6        5 8
10 "vi
+ 12
J15
L CH3 14      13 J
► ZOOM of coupled region of most deshielded signals
coupled spectrum
► spectrum with decoupling
128.5 Hz
JUL
165.9 153.7
131.5 115.5 113.1
ppm
~5tU ^77" 50.0
8.7 0
C-NMR 3, b - zoom of right region, a - full decoupled spectru
1D lciC-NMR 4, consider equilibrium minor-major form
Next topic
Vector Model + 13C APT experiment