Theoretical study of two coumarin derivatives photosensitivity for possible use in photodynamic therapy

The dynamism of cancer and its side effects related to different treatments are real questions for humankind to solve. Thus, this manuscript aims to explore the photochemical and photo-physical properties of two coumarin molecules due to their multiple biological and spectroscopic activities ¹ in the framework of photodynamic therapy (PDT) as a photosensitizer (PS). For our aim fulfillment, quantum chemical methods such as DFT and TD-DFT at the B3LYP/6-31G(d,p) level were used in different media ² to determine the parameters quoted above. The obtained results show that the solvent's nature influences the compounds' photosensitivity ³. Thus, both compounds M1 and M2 are coumarins. M1 and M2 belong to benzocoumarin and simple coumarin families, respectively. In other words, the coumarin ring of M1 is attached to a benzene ring. Apart from this difference, compound M1 contains a triazol ring, and compound M2 contains an oxadiazol ring. These compounds produce charged radicals. Moreover, compound M1 presents the lowest values of VIP and the energy of the excited state ET necessary for producing charged radicals. Therefore, it is assumed to be the most photosensitive, and this photosensitivity is more accentuated in polar solvents. In sum, studied coumarins, in addition to being used in chemotherapy, can also be used in PDT as PS. However, the theoretical improvement of the studied parameters would be a significant advance for the experimenter.