Analysis of complex hydroxyl absorptions of amino- and dimethylamino-phenols

Abstract

Multiple medium strong bands in solid aminophenols and ortho- and para-dimethylaminophenols at 3100–2300 cm^–1 were found to result from Fermi resonance interaction between the hydroxyl stretching band of the strong intermolecular O—H…N hydrogen bond and the overtone and combination bands of (ν_C—O+δ_O—H) as well as other fundamental vibrational modes of the molecules. The simplified band structure in the deuterated analogues is explainable on the decrease in the number of overtones and combinations of (ν_C—O+δ_O—D) interacting with ν_O—D.