Molecular orbitals and electronic spectra of benzo-fused and related porphyrin analogues

Molecular orbital (MO) calculations of more than 60 porphyrinic pi conjugat ed structures have been performed within the framework of the Pariser-Parr- Pople approximation. The results of a series of compounds are introduced an d summarized in order to show how they vary depending on the systematic cha nge in molecular structure. These are shown schematically or itemized. Our results are compared with the spectra of the corresponding known compounds and with the MO results reported by previous workers, if available. In addi tion, the results have continually been compared, where possible, with thos e of tetraazaporphyrin or phthalocyanine systems. In naphthalene- or anthra cene-fused compounds, these molecule-centered orbitals often appear, and th ese are indicated using either triangles or circles in figures if they appe ar between HOMO - 3 and LUMO + 3 orbitals. Copyright (C) 2001 John Wiley & Sons, Ltd.