Electronic absorption spectra of heterocyclic analogs of trans-chalcone

Thiophene, furan, and pyrrole analogs of trans-chalcone have UV spectra consisting of bands belonging to the spectra of the corresponding 2-acetylhetaryls and 2-hetarylideneacetones that are shifted bathochromically as a result of mutual perturbation of these two crossconjugated fragments. The absorption curves of 10 chalcones in hexane solution were measured up to 190 nm, the bands of the individual transitions were isolated graphically, and the degree of localization of the electron excitation on the fragments of the molecules was calculated by a new quantum-chemical method.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1202–1205, September, 1977.