Biological Activities of Phthalocyanines–vii. Photoinactivation of V‐79 Chinese Hamster Cells by Selectively Sulfonated Gallium Phthalocyanines

Gallium chloride phthalocyanines sulfonated to different degrees were tested for their ability to inactivate V‐79 Chinese hamster cells in the presence of red light. The mono‐ and disulfonated compounds were the most active whereas the tri‐ and tetrasulfonated complexes were completely void of photoactivity. In addition, large variations in photoactivity were observed among the four isomeric disulfonated derivatives with the most hydrophobic isomer exhibiting the highest photoactivity. Prolonged exposure to the disulfonated complex resulted in increased photosensitization. Complexing the dye with Al instead of Ga resulted in a slightly increased photosensitizing effect.