ON THE ELECTRONIC STATES OF MACROCYCLES OF THE EXTENDED PORPHYRIN FAMILY AND THEIR COORDINATION-COMPOUNDS

The electronic absorption spectra of Ni, Zn and Mg hemiporphyrazine de rivatives are presented and discussed together with theoretical result s obtained by INDO/S computations. The absorption spectra of all the m etal derivatives show marked red shifts of the lowest energy absorptio n bands with respect to those of the metal free hemiporphyrazine. The possible explanation that in metal derivatives low lying excited state s with a fully conjugated pi electron system are present is supported by theoretical computations.