Synthesis, photophysical properties, anti-Kasha photochemical reactivity and biological activity of vinyl- and alkynyl-BODIPY derivatives

New photoactivable BODIPY fluorescent dyes, which are quinone methide (QM) precursors, were synthesized. The series of BODIPY dyes has a photoreactive group linked to the BODIPY core by vinyl or ethynyl spacers. Molecules have bathochromic shifted absorption and emission maxima and higher fluorescence quantum yields compared to the previously reported BODIPY QM precursors. They show anti-Kasha photochemical reactivity and undergo photomethanolysis reaction upon photoexcitation at λ < 350 nm. Although UV light is needed for the photochemical generation of QMs and attachment to potential bio-targets, bathochromic shifted absorption and emission has advances in sensing and fluorescence labeling. Antiproliferative investigation was conducted for the vinyl derivative against three human cancer lines with the cells kept in dark or irradiated. Upon excitation with visible light antiproliferative activity was enhanced with IC50 values in low micromolar concentration.