Infrared spectral charateristics of the cyclobutane ring system

Abstract

In an attempt to clarify characteristic cyclobutane ring frequencies, the infrared spectra of imides and amides derived from cyclobutanecarboxylic acids have been studied. The relative constancy of a 935–900 cm^–1 band indicates it to be characteristic of the cyclobutane ring, especially when bands occur at 3000–2800 cm^–1. A band at 1250 cm^–1 could be the most useful distinguishing spectral characteristic of cyclobutanes. A band due to ring CH at a substitution site appears with great consistency at 2874–2855 cm^–1.