Chapter 20: Carboxylic Acid Derivatives

Spectroscopic Analysis of Nitriles

• IR  - very characteristic C≡N stretch (only C≡C is similar region)

Absorbance (cm-1)	Interpretation
2250	C≡N stretch

• ¹H NMR - only protons adjacent to C≡N are likely to be characterisitic.

Resonance (ppm)	Interpretation
2 - 3	H-C-C≡N


 
• ¹³C NMR

C≡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.

© Dr. Ian Hunt, Department of Chemistry