Electronic Structures of Thianthrene, Phenothiazine, and Related Heterocyclic Compounds

Systematic studies were made on thianthrene, phenoxathiin, diphenylene dioxide, phenothiazine, and phenoxazine for the correlation between the folded structure and electronic spectra in terms of the semiempirical SCF–MO–CI method. The calculated results are in good agreement with the experimental results, the folded structure being prominent in the sulfur-containing molecules. The dihedral angle dependency of the all valenceelectronic energy and ionization potential was also studied by the extended Huckel method.