Brominated BODIPYs as potential photosensitizers for photodynamic therapy using a low irradiance excitation

The synthesis, chemical, and optical characterization of three BODIPY derivatives are reported. The photogeneration of singlet oxygen for molecules was investigated in different solvents, inclusive in aqueous solution. Photocytoxicity of BODIPY was investigated on HeLa cell Line by using low irradiance excitation at 532 nm. [Display omitted] Three novel BODIPY-chromophores 4, 6 and 7 were synthesized by simple condensation reaction of thiocarboxaldehyde and pyrrole ring. Molecular structures were designed to contain thiophene rings and different arrangements for bromine substitution. The effect of these arrangements on the generation of singlet oxygen and optical properties was studied. In general, the presence of thiophene rings produces red-shifts in absorption spectra while three bromine substitution (6) tend to produce the largest singlet oxygen generation. Results show that these BODIPYs are excellent chromophores with high absorption coefficient, however they are poor fluorophores (with quantum yields