Chapter 20: Carboxylic Acid Derivatives
Spectroscopic analyzis of Nitriles
IR -
very characteristic C
º
N stretch (only C
º
C is similar region)
Absorbance (cm
-1
)
Interpretation
2250
C
º
N stretch
1
H NMR
- only protons adjacent to C
º
N are likely to be characterisitic.
Resonance (ppm)
Interpretation
2 - 3
H
-C-C
º
N
13
C NMR
C
º
N typically 115 -125 ppm (deshielding due to N)
minimal intensity, characteristic of C's with no attached H's
UV-VIS
Simple nitriles usually show no absorption above 200 nm.
Mass Spectrometry
Molecular ion M+ is often weak or absent, but a weak M-1 peak due to loss of an
a
-H is often present.
