Imides, infrared frequencies

The infrared absorption spectrum of sulfacetamide sodium has been determined in KBr disc (4). The principal peaks appear at 825, 1090,1145,1264,1552,1600 cm 1. The infrared stretching frequencies of the amino group have been used to calculate the force constant, the band angle and the "S" character of the nitrogen orbitals of the N-H band (23,24). Infrared measurements of sulfonamides have been performed to study the imide-amide tautomerism (25) and to see if there is any change in the electronegativity of the SO2 group (26,27). Sulfacetamide in eye-drops and ointments has been identified by attenuated total reflectance (ATR) infrared spectra (28). 

Hydantoins show two bands in the carbonyl region at about 1720 and 1780 cm-1. However, their interpretation has been the subject of controversy. The low-frequency band has been attributed both to the C-4168 and the C-2 carbonyl group.169 Infrared and Raman spectra have also been interpreted in terms of carbonyl coupling similar to that found in imides.170 Other studies have confirmed this coupling.171... 

---