Development of Phenanthrene‐Based Photoactivatable Fluorescent Probes and Their Cellular Imaging

Abstract This study presents the synthesis and characterization of novel phenanthrene formaldehyde hydrazone ( FS1 and FS2 ) as photoactivatable fluorescent probes (PFPs). Initially, FS1 and FS2 exhibit quenched fluorescence due to the photoinduced electron transfer (PET) effect. However, upon exposure to specific UV wavelengths, the hydrazone bond undergoes photolysis, releasing phenanthrene formaldehyde and restoring its fluorescence. The effectiveness of FS1 and FS2 as PFPs was further validated through cellular imaging experiments, demonstrating their potential for use in live‐cell imaging. This work offers a new structural option for the design of new PFPs, overcoming some of the limitations of traditional phenanthrene probes. Furthermore, this research provides a new perspective on the development of phenanthrene‐hydrazone hybrids as PFPs, offering a promising tool for advanced fluorescent probes.