C8953
NMR structural analysis - seminar
1D 13C-NMR Kateřina Peterková, Aleš Novotný
42 3 97 7@mail.muni.cz
March 13, 2019
Control of 1D 1H NMR spectrum of cartilagineal
dd    8.5 Hz
vs 13C NMR
H 13C
Spin number	1H:s=| x 2H:s=1	13C:s=| 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
□ 3>
vs 13C NMR
	1H	13C
Spin number	1H:s=| x 2H:s=1	13C:s=| 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)r+0.51J,
HC <
wc-0.51JHC
1H-13Ca
1H-13C(3
Ha-13C
12,
Hp-13C
1H decouple^.
-       I .00,0
Important regions of 13C chemical shifts
_i_
Aldehydes RCH=0
Ketones R1R2C=0 I-1
R2C—CH2
C-F
RoC=CH,
RHC=CHR h Alkenes
Aromatics Heteroaromatics
Carboxylic acids R-C02H
Esters R-C02R' I-1
Amines R-CONR2' I-1
! RC=N !
C-l
C-Br
H
C-NO;
C-H Saturated Hydrocarbons
H h
C-NH;
C-OH
C-SR
C-OR
C-S02R r-C=C I--H UU U—I
C=CR
Alkynes
H C-CO R
150
"1-
100
ppm(5)
50
200
0.0
□ 3>
=       9 ^O^o
1 Jch depends on the bond order ( hybridization <^> s-character)
► -C-H 1JCH ~ 125 Hz
► =C-H 1JCH ~ 160 Hz
► =C-H 1JCH ~ 250 Hz
► X-C-H
► X = N, O, S, F, CI, ...1 Jqh 1t
> X = Li, Mg, ...1JCH4
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 of 1H energy levels during decoupling enhances relatively intensity of 13C signals because of heteronuclear nOe    quaternary carbons usually less intensive.
Values of chemical shift of important solvents
Abbr.	Formula	1H	13C
ACN	CH3CN	1.9	118
Benzene	CeHe	7.2	128
	CHCI3	7.2	77
DCM	CH2CI2	5.3	54
DMF	(CH3)2NCHO	2.9, 8.0	32, 163
DMSO	(CH3)2SO	2.5	40
MeOH	CH3OH	3.3, 4.8	49
Water	H20	4.8	-
EXPLAIN effect of solvent on the position of residual1H water
signal:
CHCI3 -1,6, ACN - 2.1, DMSO - 3,3, MeOH - 4,9
How many 13C signal would you expect in the NMR spectrum?
H
N
CI
Ru
N
CI
CI
S
o'VCH3
CH3
N
□ 3>
=       9 ^O^o
1D 13C-NMR 1, bottom without CPD
ppm 59.0 33.0 20.3 13.7
C-NMR 2
2 3
H2N
I// W//
6        5 g
10
l-UC
J15
CI H
11 \
J14 CH3 -"14      13 J
158.9
158.9
L
JUU
U9.4 UO.O 142.0
► ZOOM of coupled region of most deshielded signals
coupled spectrum
► spectrum with decoupling
128.5 Hz
155.9 153.7
131.5 115.5 113.1
JUL
ppm
-1-r~i—
58.4 47.7 50.0
8.7 0
1D 13C-NMR3, b - zoom of right region, a - full decoupled spectrum
1D 13C-NMR 4, consider equilibrium minor-major form
Next topic
Vector Model + 13C APT experiment