Nature of the optical properties of ethionamide and prothionamide in the ultraviolet region of the spectrum

A study of the experimental and theoretical spectra of ethionamide and prothionamide molecules shows that absorption at a wavelength of 292 ± 1 nm corresponds to an electron transition between occupied and vacant p-orbitals of the C=N double bond in the structure of pyridine, while absorption at 222 ± 1 nm corresponds to a transition between the occupied and vacant p-orbitals of the С=С bond in the structure of pyridine, and to a transition between the occupied and vacant p-orbitals of the С=S chromophore. © 2017, Allerton Press, Inc.