Study of Spectral-Luminescent Properties during Photolysis of Sulfanilamide in Aqueous Solution

The electronic absorption spectra of the neutral form of an aqueous solution of sulfanilamide and their changes under irradiation with the ultraviolet light sources KrCl, XeBr, XeCl, and UVb-04 are investigated. Quantum-chemical calculations are used to identify the photoproducts. It is shown that the cationic form of SA is responsible for the fluorescence in the 340 nm region, and the anionic form of the molecule, which is formed as a result of the cleavage of the N7–H bond of the amino group of the aniline fragment of sulfanilamide, is responsible for the fluorescence of the photoproduct in the 400 nm region. The anionic form of sulfanilamide also determines the position of the long-wavelength band with λ = 310 nm in the absorption spectra of the irradiated solution.