Rational Perturbation of the Fluorescence Quantum Yield in Emission-Tunable and Predictable Fluorophores (Seoul-Fluors) by a Facile Synthetic Method Involving CH Activation

• Published in: Angewandte Chemie International Edition Vol. 53; no. 5; pp. 1346 - 1350
• Main Authors: Choi, Eun Joung, Kim, Eunha, Lee, Youngjun, Jo, Ala, Park, Seung Bum
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 27.01.2014; WILEY‐VCH Verlag; Wiley
• Subjects: Accessibility; Activation; Carbon - chemistry; Catalysis; Chemistry; Chemistry, Multidisciplinary; Communication; Communications; Cycloaddition Reaction; CH activation; Design engineering; Electron Transport; Electronics; Fluorescence; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; fluorophore design; Heterocyclic Compounds, 4 or More Rings - chemical synthesis; Heterocyclic Compounds, 4 or More Rings - chemistry; Hydrogen - chemistry; Imaging; Palladium - chemistry; Physical Sciences; Pyrroles - chemical synthesis; Pyrroles - chemistry; Quantum Theory; quantum yield; Reactive Oxygen Species - chemistry; Science & Technology; Strategy; switchable sensors; Synthesis; switchable sensors; DESIGN; SENSORS; quantum yield; CELL BIOLOGY; PROBES; C-H activation; fluorophore design; CORE SKELETON; fluorescence; BIOPROBE; HYDROGEN-PEROXIDE; LIVING CELLS; CH activation
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201308826

Fluorescence imaging enables the uniquely sensitive observation of functional‐ and molecular‐recognition events in living cells. However, only a limited range of biological processes have been subjected to imaging because of the lack of a design strategy and difficulties in the synthesis of biosensors. Herein, we report a facile synthesis of emission‐tunable and predictable Seoul‐Fluors, 9‐aryl‐1,2‐dihydrolopyrrolo[3,4‐b]indolizin‐3‐ones, with various R1 and R2 substituents by coinage‐metal‐catalyzed intramolecular 1,3‐dipolar cycloaddition and subsequent palladium‐mediated CH activation. We also showed that the quantum yields of Seoul‐Fluors are controlled by the electronic nature of the substituents, which influences the extent of photoinduced electron transfer. On the basis of this understanding, we demonstrated our design strategy by the development of a Seoul‐Fluor‐based chemosensor 20 for reactive oxygen species that was not accessible by a previous synthetic route. It's all in the design: Seoul‐Fluors with predictable photophysical properties, including a fluorescent reactive‐oxygen‐species sensor that was not previously accessible, were synthesized efficiently by coinage‐metal‐catalyzed intramolecular 1,3‐dipolar cycloaddition and subsequent palladium‐mediated CH activation (see scheme). The quantum yield of the products could be controlled systematically by altering the electronic nature of the substituents.