One- and Two-Photon-Induced Photochemistry of Modified Palladium Porphyrazines Involving Molecular Oxygen

Abstract— Octaphenyltetraanthraporphyrazinato palladium undergoes a self-sensitized photoreaction in the presence of oxygen to form a substituted palladium phthalocyanine with four endoperoxide bridges. This compound exhibits photophysical behavior similiar to palladium tetra-tert- butyl-phthalocyanine. The phthalocyanine-palladium complex with four endoperoxide bridges ejects molecular oxygen when excited by consecutive two-photon absorption in the Q-band region at 662 nm. This photocyclo-reversion, which produces palladium porphyrazines bearing a diminished number of endoperoxide bridges, can occur up to four times per initial molecule. Irradiation of these photoproducts in the presence of oxygen produces substituted palladium phthalocyanine containing four endoperoxide groups.