Theoretical aspects of the spectroscopy of porphyrins and phthalocyanines

Abstract

The development of theoretical models that describe the electronic structures of the porphyrins and phthalocyanines using ZINDO and DFT techniques is rapidly approaching the point where the major spectral bands over a wide energy range, for both symmetric and non–symmetric molecules can be fully accounted for. However, although there has been much recent progress, theoretical models should always be tested accuracy by reference to the most recent electronic absorption and magnetic circular dichroism spectra available. This must be carried out by calculating absorption spectra to determine whether the major spectral features determined are accurately described. Spectroscopists need to provide fully analyzed data for this purpose as well as data recorded at low temperatures to enhance resolution. Since the porphyrin and phthalocyanine rings readily undergo oxidation and reduction, and well-characterized spectral data are available for many different redox states, new theoretical studies should also include the bands observed in the anion and cation radical species, as well as those of the neutral complex. This symposium addresses these goals by bringing together theoreticians and experimentalists to discuss their results.