organic practicals nmr data
DESCRIPTION
Organic chemistry data for nuclear magnetic resonance (NMR) NMR Spectroscopy.TRANSCRIPT
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JS Organic Practical Course
Additional NMR spectra to aid structural determination
Three types of data are supplied :-2D homonuclear corelation spectra (HH COSY)-2D heteronuclear corelation spectra (CH COSY)-1D Nuclear Overhauser spectra (NOE)
Data is supplied for experiments :-2 (Benzoin), 3b (1,4-Diphenyl-1,3- butadiene)-5 (2,6-Dimethyl-3-heptan-5-one)-6a (1-Phenylbutane-1,4-diol)-6b (-Phenyl--butyrolactone)-7 (cis-Caran-trans-4-ol)
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Additional NMR analysisconnections through bonds and space
Correlation Spectra (COSY) through bond connectionsHH COSY - connections of proton spins through bondsCH COSY- direct link of carbon to proton(s)Long range CH COSY
Connections through spaceNuclear Overhauser (NOE) experiments
1D : Difference NOE, DPFGSE-NOE2D : NOESY, ROESY
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How to read a COSY HH COSY
diagonal is the 1D spectrumoff diagonal signal(s) display the connections of the spinstrue signal must have mirror image across the diagonal
CH COSYsignals are the direct correlation between the C and H
Long range CH COSYoften can correlate several protons to a carbon(or vice versa - whichever is most appropriate )e.g. links carbon signals with NO protons directly attached
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2 CH COSY Benzoin
(ppm) 8.0 7.2 6.4 5.6 4.8
(pp
130
120
110
100
90.0
80.0
(ppm) 8.00 7.80 7.60 7.40
(pp
134
132
130
128
126
Expansion of aromartic region
Direct correlation of
hydrogen to carbon resonances1H axis
13C axis
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3B CH COSY (E,E)-1,4-Diphenyl-1,3-butadiene
(ppm) 7.40 7.20 7.00 6.80 6.60
(pp
134
132
130
128
126
1
2
3
41'2'
3'
4' 6'5'
Direct correlation ofhydrogen to carbon resonances
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3B HH COSY (E,E)-1,4-Diphenyl-1,3-butadiene
(ppm) 7.60 7.40 7.20 7.00 6.80 6.60
(pp
7.60
7.40
7.20
7.00
6.80
6.60
6.40
(ppm) 7.60 7.40 7.20 7.00 6.80 6.60
(pp
7.60
7.40
7.20
7.00
6.80
6.60
6.40
1
2
3
41'2'
3'
4' 6'5'
Diagonal contains the 1D spectrum
Connections between atoms are symmetrical about the diagonal
Generally, the higher the contourthe stronger the connection
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5 HH COSY 2,6-Dimethyl-5-hydroxyheptan-3-one
(ppm) 4.0 3.2 2.4 1.6 0.8
(ppm)
3.2
2.4
1.6
(ppm) 2.8 2.4 2.0 1.6 1.2 0.8
(ppm)
2.4
2.0
1.6
1.2
1H
1H
O OH
12
3
4
5
6
7
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5 CH COSY 2,6-Dimethyl-5-hydroxyheptan-3-one
(ppm) 3.6 3.2 2.8 2.4 2.0 1.6 1.2
(ppm)
72
64
56
48
40
32
24
16
(ppm) 1.12 1.08 1.04 1.00 0.96 0.92 0.88
(ppm)
18.8
18.4
18.0
17.6
17.2
1H
13C
O OH
12
3
4
5
6
7
Methyl region
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5 CH COSY 2,6-Dimethyl-5-hydroxy-heptan-3-one
(ppm) 2.72 2.64 2.56 2.48 2.40
(ppm)
44.8
44.0
43.2
42.4
41.6
40.8
40.0
Expansion of the 2.40-2.75ppm region
CH
-CH2-
Spin-Spin Coupling informationfrom the CH2 (Hz)
2.56ppm2.45ppm
2.54ppm
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5 Long Range CH COSY 2,6-Dimethyl-5-hydroxyheptan-3-one
(ppm) 3.6 3.2 2.8 2.4 2.0 1.6 1.2
(ppm)
200
160
120
80
40
Notice CH correlations to :
- a longer range i.e. two or more bonds for a CH correlation
- a carbonyl resonancei.e. a quaternary peak
- a hydroxyl peak
Keto Carbon 216 ppm
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6A CH COSY of 1-Phenyl-1,4-butanediol
(ppm) 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00
(ppm)
120
100
80
60
40
(ppm) 7.40 7.36 7.32 7.28 7.24
(ppm)
130.0
128.0
126.0
124.0
122.0
OH
HO1H
13C
1
23
4o,m 1H signalsoverlap
p
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6A HH COSY of 1-Phenyl-1,4-butanediol
(ppm) 7.2 6.4 5.6 4.8 4.0 3.2 2.4 1.6
(ppm)
7.2
6.4
5.6
4.8
4.0
3.2
2.4
1.6
OH
HO
1
2
34
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6B CH COSY -Phenyl--butyrolactone
(ppm) 8.00 7.00 6.00 5.00 4.00 3.00 2.00
(pp
140
120
100
80
60
40
(ppm) 2.80 2.60 2.40 2.20 2.00 1.80
(pp
36
32
28
24
(ppm) 7.68 7.60 7.52 7.44 7.36 7.28 7.20 7.12
(pp
130
128
126
124
122
OOH
41
3 2
2
64
3
5
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7 CH COSY cis-caran-trans-4-ol
(ppm) 3.2 2.8 2.4 2.0 1.6 1.2 0.8
(ppm)
72
64
56
48
40
32
24
16
(ppm) 2.00 1.80 1.60 1.40 1.20 1.00 0.80
(ppm)
36
32
28
24
20
16
HCH3
OH
HH
HCH3CH3
(ppm) 2.0 1.6 1.2 0.8
(ppm)
32
28
24
20
16
Me
Me
Me
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7 HH COSY cis-caran-trans-4-ol
(ppm) 3.2 2.8 2.4 2.0 1.6 1.2 0.8
(pp
3.2
2.8
2.4
2.0
1.6
1.2
0.8HCH3
OH
HH
HCH3CH3
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7 HH COSY cis-caran-trans-4-ol
(ppm) 3.2 2.8 2.4 2.0 1.6 1.2 0.8
(pp
3.2
2.8
2.4
2.0
1.6
1.2
0.8
(ppm) 3.2 2.8 2.4 2.0 1.6 1.2 0.8
(pp
3.2
2.8
2.4
2.0
1.6
1.2
0.8
HCH3
OH
HH
HCH3CH3
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More complex NMR experiments to detemine the configuration of the cis-Caran-trans-ol
Long range CH COSYused to find correlations to proton(s) other than those directly attached to a carbonused to establish links to hydroxy groups and quaternary carbon peaks
Nuclear Overhauser Effect (NOE) This will etablish interactions of the spins through SPACEDifference NOE experiment irradiate a specific proton and observe any changes(a normal spectrum is subtracted from the irradiated spectrum to give the DIFFERENCE spectrum
expect to differentiate between the two methyl peaks on the cyclopropyl ringone should be lying in the same plane as the two cis protons on the ring
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7 Long range CH COSY cis-Caran-trans-ol
(ppm) 4.0 3.2 2.4 1.6 0.8
(ppm)
72
64
56
48
40
32
24
16
OH
H
H
HOH
H
HH
H
CH3
H
CH3CH3
12
3
78
5
2'
6
9
4
Solvent DMSO-d6
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7 Difference NOE NMR cis-Caran-trans-4-ol
0.81.01.21.41.61.82.02.22.42.62.83.0
0.81.01.21.41.61.82.02.22.42.62.83.0
0.81.01.21.41.61.82.02.22.42.62.83.0(ppm)
Normal Spectrum
Difference Spectrum Methyl at 0.93 ppmirradiated
Methyl at 0.89 ppmirradiated
Positive NOE
No NOE