With increasing attention recently, photodynamic therapy (PDT) has been investigated and applied in different branches of medicine, with focus in cancer therapy. The progress of PDT as an alternative or complementary treatment to the conventional ones is mainly due to the development of new photosensitizers (PSs) that allow for higher treatment efficiency with minimal side effects to the patient and lower cost. Porphyrins represent a class of widely investigated PSs owing to their unique photochemical properties and high versatility. Porphyrazines, on the other hand, are still scarcely studied porphryin derivatives that, despite the structural resemblance, show distinct electronic properties with high absorption in the near infrared region - essential requirement for last generation PSs. A disadvantage of porphyrinoids, however, is the central ring susceptibility to oxidative attack from reactive oxygen species (ROS) produced during the photosensitization process, resulting in the destruction of the macrocycle (photobleaching) and loss of its properties. In this context, this research project aims the synthesis of octaarylporphyrazines bearing substituents with distinct electron withdrawing capacities in order to modulate the macrocycle´s oxidation potential, and correlation with the photobleaching tendency quantitatively. Apart from investigating the singlet oxygen production efficiency, these compounds will be incubated in cells for localization and cell death studies, aiming to elucidate their potential applicability as PSs in PDT. The use of arylporphyrazins in cells is unprecedented and may represent a significant contribution to the development of photosensitizers for PDT.
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