The Cytological Effects of Podophyllin

Abstract

Zinc chlorin and chlorophyll showed phosphorescent bands starting in the range of 7,800-8,000 A and extending into the infrared. The lifetime of the phosphorescent state of these 2 is estimated in the region of 0.2 sec. No phosphorescence could be observed for copper chlorin on the phosphorscopc used, which fact puts an upper limit to the life of a meta-stable state for this substance at about 10-5 sec., if such a state exists at all. If these metastable states are triplet states whose life is prolonged by the triplet-singlet selection rule prohibition, the failure of the copper salt to exhibit phosphorescence is due to the breakdown of this selection rule by the inhomogeneous magnetic field produced within the molecule by the paramagnetic moment of the copper. This result was also predicted from the exptl. observation that the copper chlorin is not at all comparable in photochemical activity with the zinc salt, although the 2 compds. are otherwise very similar, especially in absorption spectrum.