Halogen atom effect on photophysical and photodynamic characteristics of derivatives of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin

Brominated and iodinated derivatives of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin were synthesised directly from the corresponding aldehydes. Photophysical and photochemical properties, singlet oxygen formation quantum yields, photobleaching and log P were measured. Cellular uptake measurements and cytotoxicity assays on WiDr and A375 tumour cell lines were performed. 5,10,15,20-Tetrakis(2-bromo-5-hydroxyphenyl)porphyrin showed the best cytotoxicity with values of IC50 of 113 nM over WiDr cells and 52 nM over A375 cells.