Improved brightness of multiarylpyrroles in the near-infrared region via coordination-induced supramolecular system

Organic fluorescent dyes that emit in the near-infrared region offer many benefits in biological imaging; nevertheless, their low fluorescence quantum yield remains problematic. In this study, we synthesized an aggregation-induced emission dye from multiarylpyrroles (MAPs) and continuously increased the fluorescence intensity by coordinating the MAPs with tris(pentafluorophenyl)borane (BCF). The coordination between MAPs and BCF improved the fluorescence quantum yields without changing the emission wavelength by increasing the intramolecular interactions and restricting the molecular motion. Moreover, experimental and theoretical calculations verified that the ability to produce reactive oxygen species decreased after coordination, which was beneficial for long-term fluorescence imaging tracking. The coordination between near-infrared dyes and BCF not only provides general guidance for improving the quantum yield but also regulates the charge transfer between the singlet and triplet states, which influences the production of reactive oxygen species.