Infrared spectra of several 1,3-dicarbonyl compounds from different organic chemical classes have been recorded. Assignments of characteristic enol frequencies have been made, and group frequency ranges developed. In most cases, the ranges are reasonably narrow considering the great changes in overall structure of the examples studied. The enol structure affects to a significant degree the absorption frequencies of certain modes.
David W. Schiering and J. E. Katon, "Characteristic Infrared Absorption Frequencies of the Enol Group of 1,3-Dicarbonyl Compounds," Appl. Spectrosc. 40, 1049-1054 (1986)