Download Approximate Proton Chemical Shifts

Approximate Proton Chemical Shifts
Type of Proton
Typical structure
Chemical Shift
(ppm)
o
RCH3
RCH2R
0.8 - 1.0
1.2 - 1.4
3 Alkyl
o
R3CH
1.4 - 1.7
Allylic
R2C=C(R)-CH3
1.6 - 1.9
Ketone
RCOCH3
2.1 - 2.6
1 Alkyl
o
2 Alkyl
Benzylic
ArCH3
2.2 - 2.5
Acetylenic
2.5 - 3.1
RC≡C-H
RCH2I
3.1 - 3.3
Alkyl iodide
ROCH2R
3.3 - 3.9
Ether
HOCH2R
3.3 - 4.0
Alcohol
RCH2Br
3.4 - 3.6
Alkyl bromide
RCH2CI
3.6 - 3.8
Alkyl chloride
R2C=CH2
Vinylic
4.6 - 5.0
R2C=C(R)H
5.2 - 5.7
Vinylic,
ArH
Aromatic
6.0 - 9.5
RCOH
Aldehyde
9.5 - 10.5
ROH
Alcohol
0.5 - 6.0*
RNH2
Amino
1.0 - 5.0*
ArOH
Phenolic
4.5 - 7.7*
RCOOH
Carboxylic
10.0 -13.0*
*The chemical shifts of these protons vary in different solvents, and with
temperature and concentration
Approximate Carbon-13 Chemical Shifts
Type of Carbon
Chemical Shift (ppm)
o
1 Alkyl
0 - 40
o
2 Alkyl
10 - 50
o
3 Alkyl
10 - 50
Alkyl halides or amines
10 - 65
Alcohols or ethers
50 - 90
Alkynes
60-90
Alkenes
100 -170
Aryls
100 -170
Nitriles
120-130
Amides
150-180
Carboxylic acids, esters
160-185
Aldehydes, ketones
185-215
Characteristic Infrared Absorptions of Functional Groups
Group
Frequency
Intensity
-1
(cm )
A. Alkyl
C-H stretch
B. Alkenyl
=C-H stretch
C=C stretch
C. Alkynyl
≡C-H stretch
C≡C stretch
≡C-H bend
D. Aromatic
Ar-H stretch
CC stretch
E. Alcohols (OH stretch)
dilute solutions, OH stretch
hydrogen-bonded, OH stretch
C-O stretch
2853 - 2962
(m-s)
3010 - 3095
1620 - 1680
(m)
(v)
~3300
(s)
(v)
(s)
2100-2260
600 -700
~3030
1600-1585
(v)
3590-3650
(sharp, v)
3200-3550
(broad, s)
1050-1200
(s)
1070-1150
(s)
C=O stretch
1690-1740
(s)
C-H stretch
2720 -2820
(m)
1680-1750
(s)
1735-1750
(s)
1710-1780
(s)
2500-3000
(broad, v)
C=O stretch
1630-1690
(s)
N-H stretch
3350-3500
(s-m)
3300-3500
(m)
2220-2260
(m)
NO2 stretch (asym)
1500-1660
(s)
NO2 stretch (sym)
1260-1390
F. Ethers
C-O stretch
G. Aldehydes
H. Ketones
C=O stretch
I. Esters
C=O stretch
J. Carboxylic acids
C=O stretch
Hydrogen-bonded OH stretch
K. Amides
L. Amines
N-H stretch
M. Nitriles
C≡N stretch
N. Nitro compounds
s = strong, m = medium, w = weak, v = variable, ~ = approximately
Element
Carbon
Hydrogen
Nitrogen
Oxygen
FIuorine
Silicon
Phosphorus
Sulfur
Chlorine
Bromine
Iodine
Stable Isotopes of Common Elements
M+1 Isotope (%)
Most Common
Isotope
12
C
H
14
N
16
O
19
F
28
Si
31
P
32
S
35
Cl
79
Br
127
I
1
100
100
100
100
100
100
100
100
100
100
100
13
C
H
15
N
17
O
2
29
Si
33
S
1.11
0.016
0.38
0.04
M+2 Isotope (%)
18
O
0.20
5.10
30
Si
3.55
0.78
34
S
Cl
81
Br
4.40
32.5
98.0
37