The electronic absorption spectra of some coumarins. A molecular orbital treatment

摘要: The electronic absorption spectra of coumarin and its derivatives umbelliferone (6-hydroxycoumarin), esculetin (6,7-dihydroxycoumarin), scopoletin (6-methoxy-7-hydroxycoumarin) were investigated. n → π* transition was not observed in the spectrum but some derivatives. Molecular orbital calculations, using INDO procedures, carried out on activities different sites molecules are discussed terms coefficients atomic orbitals constituting HOMO LUMO. correspondence between calculated experimental energy band intensity is satisfactory.