Near-Infrared-Emitting Hemicyanines and Their Photodynamic Killing of Cancer Cells.

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 ( 1 O 2 ) 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 (Φ Δ = 0.8) and was successfully applied in in vitro studies to mimic photodynamic therapy application.