Single-Benzene Dual-Emitters Harness Excited-State Antiaromaticity for White Light Generation and Fluorescence Imaging

Molecular emitters simultaneously generating light at different wavelengths have wide applications. With a small molecule, however, it is challenging to realize two independent radiative pathways. We invented the first examples of dual-emissive single-benzene fluorophores (SBFs). Two emissive tautomers are generated by synthetic modulation of the hydrogen bond acidity, which opens up pathways for excited-state proton transfer. White light is produced by a delicate balance between the energy and intensity of the emission from each tautomer. We show that the excited-state antiaromaticity of the benzene core itself dictates the proton movements driving the tautomer equilibrium. Using this simple benzene platform, a fluorinated SBF was synthesized with a record high solubility in perfluorocarbon solvents. White light-emitting devices and multicolor imaging of perfluorocarbon nanodroplets in live cells demonstrate the practical utility of these molecules.

Automated summary

We invented dual-emissive single-benzene fluorophores that can emit light at different wavelengths simultaneously. This was achieved by modulating the hydrogen bond acidity to generate two emissive tautomers with excited-state proton transfer pathways. The white light emitted by these fluorophores relies on the delicate balance between the energy and intensity of each tautomer's emission. We also synthesized a fluorinated single-benzene fluorophore with a record high solubility in perfluorocarbon solvents and demonstrated their practical utility in white light-emitting devices and multicolor imaging of perfluorocarbon nanodroplets in live cells.