Relationship between the photochemical properties and structure of pophyrins and related compounds

Photostability was studied and quantum yields of singlet oxygen in air-satu rated dimethyl sulfoxide were determined for phenyl-substituted zinc comple xes of porphyrin and porphyrazine and their annelated analogs. It is found that the photochemical properties of the complexes are stronger affected by linear annelation of the macroring than its angular annelation. In whole b enzene annelation in the macroring of porphyrins reduce their photostabilit y and quantum yield of singlet oxygen, while phenyl substitution favors gen eration of singlet oxygen.