The infrared bands of thiophen-2-carbaldehydes in the carbonyl region : multiple absorption caused by Fermi resonance

Abstract

Thiophen-2-carbaldehyde and 19 related aldehydes have been examined under high resolution in the i.r. CO region. It has been established that the multiple absorptions shown by many of the aldehydes are caused by Fermi resonance. Deuteriation of an aldehyde may lead to an increase in the complexity of its spectrum; bromination is also often effective in diagnosing the occurence of Fermi resonance.