N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
358
7 IR
Assignment
Range
Comments
≈3100
Dihydrazides
≈3250
Imides
In the same range: OH st, – – – CH st (≈3300, sharp), H 2 O
C=O st
(amide I)
1740–1630
Subranges:
Generally strong. In Raman, weak to medium
≈1690
NH 2 C=O free amides, H-bonded: ≈1650
≈1685
NHC=O free amides, H-bonded: ≈1660
≈1650
NC=O free amides, H-bonded: ≈1650
≈1745
4-Ring lactams
≈1700
5-Ring lactams
≈1650
6-, 7-Ring lactams
≈1670
Monohydrazides
≈1600
Dihydrazides
1740–1670
Imides
≈1750, 1700 5-Ring imides, 2 bands
1655–1630
Polypeptides
≈1690
Isocyanurates; with aromatic substitution: ≈1770
≈1720,
1755 sh
Trifluoroacetamides
NH δ and N–
C=O st sy
1630–1510
Subranges:
Generally strong, absent in lactams
(amide II)
≈1610
NH 2 C=O free, H-bonded: ≈1630
≈1530
NHC=O free, H-bonded: ≈1540
1560–1510
Polypeptides
≈1555
Trifluoroacetamides
C–N st (?)
≈1400
NH 2 C=O
≈1250
NHC=O
≈1330
Lactams
NH δ ip
≈1150
NH 2 C=O
≈1465
Lactams
NH δ oop
750–600
NH 2 C=O
≈700
NHC=O
≈800
Lactams