The infrared absorption spectra of the normal 2,4-dienaldehydes, from pentadienal through dodecadienal, were measured in the liquid state over the spectral range from 400 to 4000 cm−1. The compounds were prepared by conventional methods and purified by gas-liquid chromatographic procedures immediately before spectrophotometry. Two strong bands near 1685 and 1643 cm−1, four strong bands in the 980-1180 cm−1 region, and a doublet in the aldehyde C-H stretching region are characteristic of the n-2 trans, 4 trans dienal structure.
Glen F. Bailey and M. Nonaka, "The Infrared Absorption Spectra of the n-2 trans, 4 trans Dienaldehydes, C5 through C12," Appl. Spectrosc. 17, 156-158 (1963)