Study of Rhodamine‐Based Fluorescent Probes for Organic Radical Intermediates

Abstract

Rhodamine‐based amide derivatives for the detection of radical intermediates in organic reactions were synthesized and used as fluorescent probes over a wide range of solvents. The mechanistic studies confirm a reversible opening and closing of the spirolactam ring. Compound 21 can be used to support the radical mechanism or in the real‐time monitoring of radical intermediates.

A general photoinduced oxidative strategy with molecular oxygen in water

“…S3 †), 14 or under an argon atmosphere (Table 1, entry 3). Meanwhile, the formation of radicals was further supported by the fluorescent experiments with the addition of a rhodamine-based fluorescent probe (20) 15 for organic radical intermediates (Scheme 3d): when diacetyl was irradiated by purple light under an oxygen atmosphere, pink color and strong fluorescence were observed, but no color or fluorescence change was observed under argon, or in dark, or without the addition of diacetyl (Fig. S4 †).…”