Chapter 12 * IR Spectrum of Amides Amides will show a strong absorption for the C?O at 1630?1660 cm-1. If there are hydrogens attached to the nitrogen of the amide, there will N?H absorptions at around 3300 cm-1. Chapter 12 * Carbon?Nitrogen Stretching C?N 1200 cm-1 C?N 1660 cm-1 usually strong C?N > 2200 cm-1 For comparison, C?C < 2200 cm-1 Chapter 12 Chapter 12 * IR Spectrum of Nitriles A carbon nitrogen triple bond has an intense and sharp absorption, centered at around 2200 to 2300 cm-1. Nitrile bonds are more polar than carbon?carbon triple bonds, so nitriles produce stronger absorptions than alkynes. Chapter 12 * Summary of IR Absorptions Chapter 12 Chapter 12 * Chapter 12 *