SPECTRAL PROPERTIES AND ABSOLUTE DETERMINATION OF SINGLET OXYGEN PRODUCTION YIELD BY NAPHTHALOPORPHYRINS

The spectroscopic data of a new derivative of porphyrin are presented. The free base and Zn complex of tetranaphthaloporphyrin possess a str ong Q absorption band above 700 nm, a desired property for biological photosensitization. Intersystem crossing to the excited triplet level is efficient and the quantum yield of singlet oxygen production approa ches 0.6 in some solvents. It is shown that the yield can be determine d in an absolute manner by employing an efficient singlet oxygen targe t, 1,3-diphenyl isobenzofuran (DPIBF), under conditions in which the k inetics are of zero order and the yield can be extracted in a simple w ay.