IR Spectra Flashcards
3200–3600 (broad)
2200–3600 (very broad)
3350–3500
- Appears as a single broad
peak (but sharper than O-H)
∼3300
3000–3100
2850–3000
2750 and 2850 (two weak
signals)
~1650–1820 (strong)
1600–1700
1450–1600
1650–2000
2100–2200
2200–2300
C=O
~ 1820 and ~1760
~1790
~1735
~1730
~1720
~1715
~1650
1250–1350
1000–1100
1000–1200
600–800
500–600
680- 860 cm-1 region can help determine ortho-meta-para substitution patterns for aromatics
The region between 1650-1800 for C=O
- carbonyl groups have a very strong, sharp, distinctive peak in the region around 1700 cm-1. The exact position of the C=O vibration varies somewhat according to the type of functional group
Primary Amines
3300-3500 cm-1
- often appears as two closely spaced peaks (sharper than O-H but still somewhat broad)
Terminal Alkyne
~ 3300 cm-1
- appears as a strong, sharp peak
____________________ appear as a broad peak with jagged edges that takes up the entire area of the spectrum, and often obscure the C-H stretching peaks around 3000 cm-1
Carboxylic acids
Most prominent and distinctive peaks to look for is the ________ absorbance around
3200-3500 cm-1
- It usually appears as a broad, featureless hump
OH
In IR spectroscopy, the sample (often a thin film) is exposed to a burst of infrared light, and the absorbance of the sample is measured versus the frequency of light.
