INFRARED SPECTROSCOPY (IR)

1
INFRARED SPECTROSCOPY(IR)
2
Infrared Spectroscopy
Chemical bonds absorb energy in the IR region
related to the vibration of different
bonds. Infra-red absorbance values are reported
as units of wavelength (? , µm) or more commonly
as wave numbers (? , cm-1) which are related to
frequency. ? 1/ ? and v c/
? If ? is in cm then wave numbers are
calculated to be in cm-1. Higher frequency and
shorter wavelengths represent higher energy.



3
IR Vibrational Modes
There ate two types of bond vibrational modes
1. stretching and 2. bending
4
IR Absorbance Regions
Common Bond Stretching Regions in an IR Spectrum
5
IR Spectrum n-hexane
6
IR Spectrum 1-hexene
7
IR Spectrum 1-octyne
8
IR Spectrum 2-octyne
9
IR Spectrum di-n-propyl ether
CH3CH2CH2-O-CH2CH2CH3
10
IR Spectrum 1-butanol
11
IR Spectrum di-n-propylamine
12
IR Spectrum 2-heptanone
13
IR Spectrum butanal
14
IR Spectrum methyl benzoate
C O
15
IR Spectrum hexanoic acid
16
IR Spectrum butanamide
17
IR Spectrum butanenitrile
18
ENDINFRARED SPECTROSCOPY(IR)