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

• Published in: Angewandte Chemie 2023-05, Vol.135 (20), p.n/a
• Main Authors: Kim, Younghun, Kim, Heechan, Son, Jung Bae, Filatov, Michael, Choi, Cheol Ho, Lee, Nam Ki, Lee, Dongwhan
• Format: Article
• Language: English
• Subjects: Acidity; Aromaticity; Benzene; Chemical compounds; Chemistry; Emitters; Fluorescence; Fluorophores; Hydrogen Bonds; Luminous intensity; Materials Science; Perfluorocarbons; Photochemistry; Protons; Tautomers; Wavelengths; White light
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202302107

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. Single‐benzene dual‐emitters are realized by proton transfer equilibrium between two emissive tautomers. We demonstrate that the excited‐state antiaromaticity of the benzene core drives the proton movements. The dual‐emitters produce white light in both solution and solid states, making them useful for white light‐emitting devices and multicolor fluorescence imaging of fluorous nanodroplets in live cells.