Characteristic infrared frequencies of rotational isomers of alkyl chlorides

Abstract

A study of the infrared spectra of primary, secondary and tertiary alkyl chlorides reveals that the frequency of the so-called C-Cl stretching mode is a function of the detailed structure in the vicinity of the C-Cl bond. In primary chlorides the frequency region depends on whether a hydrogen atom or a carbon atom is irons to the Cl atom across the common C-C bond. In secondary chlorides it is found that the trans substituents on both C-C bonds adjacent to the C-Cl bond are important in determining the frequency region, and a similar result is observed for the tertiary chlorides. Frequency ranges for the various rotationally isomeric structures of primary, secondary and tertiary chlorides are given.