California State Polytechnic University, Pomona Dr....
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California State Polytechnic University, Pomona Dr. Laurie S. Starkey, Organic Chemistry Lab CHM 318L 1 H NMR Chemical Shifts 11 10 9 8 7 6 5 4 3 2 1 0 R H O H R 2 C CR H ROCH 3 CH 3 R CH 3 O RH CH 3 CH NH OH R NH 2 O NH 2 RNH 2 R OH O OH ROH δ (ppm) Type of C-H δ (ppm) Description of Proton 0.9 alkyl (methyl) 1.3 alkyl (methylene) 1.5-2 alkyl (methine) 1.8 allylic (C is next to a pi bond) 2-2.3 α to carbonyl (C is next to C=O) 2.3 benzylic (C is next to Ph) 2.5 alkynyl 2-3 α to nitrogen (C is attached to N) 2-4 α to halogen (C is attached to Cl, Br, I) 3.8 α to oxygen (C is attached to O) 5-5.3 vinylic (H is attached to alkene C) 7.3 aromatic (H is on phenyl ring) 9.7 aldehyde (H is on C=O) R CH 3 R CH 2 R R 3 C H R 2 C CR H Ar CH 3 RC C H R 2 N CH 3 R CH 2 X RO CH 3 Ar H R C H O R C CH 3 O CH 3 Protons on Carbon Type of H δ (ppm) Description ROH ArOH R C OH O RNH 2 R C NHR O ArNH 2 R CH 2 F 4.5 α to fluorine (C is attached to F) 0.5-5 alcohol 4-7 phenol 10-13 carb. acid 0.5-5 amine 3-5 aniline 5-9 amide Protons on Oxygen/Nitrogen* *Protons on N or O typically have wide ranges of expected chemical shifts; the actual δ value depends on the solvent used, the concentration, temperature, etc. Because these protons are acidic and, therefore, e x c h a n g e a b l e, they may be broad peaks and usually do not couple with neighboring protons (typically they are broad singlets). If a protic deuterated solvent is used (e.g., D 2 O or CD 3 OD), then the NH and OH protons will exchange with the deuterium and the peaks will shrink or disappear entirely, since D ( 2 H) does not show up in the 1 H NMR spectrum. R = alkyl group Ar = aromatic ring, such as phenyl (Ph) Note: aldehyde (-CHO) proton usually does not couple with neighboring H's so appears as a singlet
Transcript of California State Polytechnic University, Pomona Dr....
California State Polytechnic University, PomonaDr. Laurie S. Starkey, Organic Chemistry Lab CHM 318L
1H NMR Chemical Shifts
11 10 9 8 7 6 5 4 3 2 1 0
R H
OH R2C CR
HROCH3
CH3
R CH3
O
RH
CH3
C H
N H
O H
R NH2
ONH2 RNH2
R OH
OOH ROH
δ (ppm)
Type of C-H δ (ppm) Description of Proton
0.9 alkyl (methyl)
1.3 alkyl (methylene)
1.5-2 alkyl (methine)
1.8 allylic (C is next to a pi bond)
2-2.3 α to carbonyl (C is next to C=O)
2.3 benzylic (C is next to Ph)
2.5 alkynyl
2-3 α to nitrogen (C is attached to N)
2-4 α to halogen (C is attached to Cl, Br, I)
3.8 α to oxygen (C is attached to O)
5-5.3 vinylic (H is attached to alkene C)
7.3 aromatic (H is on phenyl ring)
9.7 aldehyde (H is on C=O)
R CH3
R CH2 R
R3C H
R2C CRH
Ar CH3
RC C H
R2N CH3
R CH2 X
RO CH3
Ar H
R C HO
R C CH3
O
CH3
Protons on CarbonType of H δ (ppm) Description
ROH
ArOH
R C OHO
RNH2
R C NHRO
ArNH2
R CH2 F 4.5 α to fluorine (C is attached to F)
0.5-5 alcohol
4-7 phenol
10-13 carb. acid
0.5-5 amine
3-5 aniline
5-9 amide
Protons on Oxygen/Nitrogen*
*Protons on N or O typically have wide ranges of expected chemical shifts; the actual δ value depends on the solvent used, the concentration, temperature, etc. Because these protons are acidic and, therefore, exchangeable, they may be broad peaks and usually do not couple with neighboring protons (typically they are broad singlets). If a protic deuterated solvent is used (e.g., D2O or CD3OD), then the NH and OH protons will exchange with the deuterium and the peaks will shrink or disappear entirely, since D (2H) does not show up in the 1H NMR spectrum.
R = alkyl groupAr = aromatic ring, such as phenyl (Ph)Note: aldehyde (-CHO) proton usually does not
couple with neighboring H's so appears as a singlet
