Abstract

The radiative deactivation of the lower excited triplet and singlet states for families of free bases and Zn complexes of water-soluble 5,10,15,20-tetrakis- -porphyrin, 5,10,15,20-tetrakis- -porphyrin, 5,10,15,20-tetrakis- -porphyrin in solutions at temperatures 77 and 293 K. It was found that the quantum yields of fluorescence and phosphorescences have small but noticeable differences for derivatives of the same porphyrin, differing the nature of the counterion of ionizable aryl substituents. It was shown that these differences are due to the effects of spin-orbital interaction, variations in the electron-donor and electron-acceptor capacities of peripheral substituents, which lead to a change in the energy of electronic states in the porphyrin-counterion system.