Oxidovanadium(V) complexes as promising anticancer photosensitizers

Photodynamic therapy (PDT) is an alternative treatment widely used against cancer. PDT requires molecular systems, known as photosensitizers (PS), which not only exhibit strong absorption at a particular wavelength range, but also need to be selectively accumulated inside cancer cells. PS are activated by specific wavelengths that cause tumor cell death by mechanisms related with oxidative stress. In this paper, three oxidovanadium(V) complexes linked to a Schiff base, which exhibit anticancer activity by displaying desirable accumulation inside malignant cells, are studied using Density Functional Theory (DFT) and Time Dependent-DFT (TD-DFT) methodologies to characterize their structural and photophysical properties as possible PS. The maximum absorption of these complexes in aqueous solution was predicted to be approximately 460 nm presenting a ligand-to-metal charge transfer. Additionally, we describe the photodynamic type reaction that these complexes can undergo when considered as PS candidates. Our results suggest that the system, containing triethylammonium as substituent, is the most suitable complex to act both as PS and as a possible therapeutic candidate in PDT.