Comparative theoretical study of the electronic structures and electronic spectra of Fe2+-, Fe+3-porphyrin and free base porphyrin

The Intermediate Neglect of Differential Overlap quantum chemical procedure , with configuration interaction, as implemented in the ZINDO program, was employed for a theoretical calculation of Fe2+-porphyrin, Fe3+-porphyrin an d free base porphyrin. The ground states for the first two species were fou nd to be, at the HF level, a triplet and a quadruplet, respectively. The ge ometries, electronic charge distribution and energy levels, as well as theo retical UV/Vis spectra, for the three species are shown. The calculated wav elengths were good agreement with the experimental values of the electronic spectra of Fe2+-porphyrin, Fe3+-porphyrin and free base porphyrin. (C) 200 1 Elsevier Science B.V. All rights reserved.