Exocyclically metallated tetrapyridinoporphyrazine as a potential photosensitizer for photodynamic therapy

摘要

We report the first exocyclically metallated tetrapyridinoporphyrazine, tetrakis-(trans-Pt(NH3)(2)Cl)-tetra(3,4-pyrido)porphyrazine-zinc(ii)(NO3)(4) (4), synthesized in a multistep synthesis starting from 3,4-pyridinedicarbonitrile (1). The synthetic procedure involved a platination reaction of the intermediate tetra(3,4-pyrido)porphyrazine-zinc(ii) (2), whereby the zinc(ii) enhanced the solubility of the intermediate enabling the platination reaction. A similar approach to synthesize tetrakis-(trans-Pt(NH3)(2)Cl)-tetra(3,4-pyrido)porphyrazine(NO3)(4) (5) failed due to the unsuitable solubility properties of the intermediate tetra(3,4-pyrido)porphyrazine (3). The final product 4 and the intermediates were characterized, the photochemical and photophysical properties were determined and the photocytotoxicities were investigated. We demonstrate that the platinated tetra-pyridinoporphyrazine 4 is a potential photosensitizer for photodynamic therapy (PDT).