A series of hemicyanine dyes was synthesized starting from the vinyl chloride-based cyanine dye IR-780. The dyes absorbed and emitted in the near-infrared region, while heavy atom (bromo and iodo) substitution promoted the generation of both singlet oxygen (1O2) as well as a range of other reactive oxygen-based species (ROS) upon irradiation at wavelengths greater than 610 nm. One hemicyanine dye displayed an outstanding singlet oxygen quantum efficiency (ΦΔ = 0.8) and was successfully applied in in vitro studies to mimic photodynamic therapy application.
Keywords: fluorescence; heavy atom; hemicyanines; near-infrared emitting; photodynamic therapy.