N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
7 IR Spectroscopy
7.1 Alkanes
Typical Ranges (v ~ in cm -1 )
Assignment
Range
Comments
C–H st
3000–2840
Intensity variable, often multiplet
Beyond normal range:
2850–2815
CH 3 –O, methyl ethers
2880–2830
CH 2 –O, ethers
2880–2835,
2780–2750
O–CH 2 –O, methylenedioxy
≈2820
O–CH–O, acetals: weak
3050–3000
O , N
2900–2800,
2780–2750
CH=O, aldehydes: Fermi resonance
2820–2780
CH 3 –N, CH 2 –N; amines
3100–3050,
3035–2995
2930–2915,
2900–2850
cyclohexanes: weak, comb at ≈2700
3080–2900
CH–hal st
CH2 δ
C–H st
CH3 δ as
CH2 δ
%T
400
800
1200
1600
2000
2800
3600
CH 3 δ sy
© The Author(s), under exclusive license to Springer-Verlag GmbH, DE,
part of Springer Nature 2020
E. Pretsch et al., Structure Determination of Organic Compounds,
https://doi.org/10.1007/978-3-662-62439-5_7
307
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
7 IR Spectroscopy
7.1 Alkanes
Typical Ranges (v ~ in cm -1 )
Assignment
Range
Comments
C–H st
3000–2840
Intensity variable, often multiplet
Beyond normal range:
2850–2815
CH 3 –O, methyl ethers
2880–2830
CH 2 –O, ethers
2880–2835,
2780–2750
O–CH 2 –O, methylenedioxy
≈2820
O–CH–O, acetals: weak
3050–3000
O , N
2900–2800,
2780–2750
CH=O, aldehydes: Fermi resonance
2820–2780
CH 3 –N, CH 2 –N; amines
3100–3050,
3035–2995
2930–2915,
2900–2850
cyclohexanes: weak, comb at ≈2700
3080–2900
CH–hal st
CH2 δ
C–H st
CH3 δ as
CH2 δ
%T
400
800
1200
1600
2000
2800
3600
CH 3 δ sy
© The Author(s), under exclusive license to Springer-Verlag GmbH, DE,
part of Springer Nature 2020
E. Pretsch et al., Structure Determination of Organic Compounds,
https://doi.org/10.1007/978-3-662-62439-5_7
307