Novel BODIPY-Fluorene-Fullerene and BODIPY-Fluorene-BODIPY Conjugates: Synthesis, Characterization, Photophysical and Photochemical Properties

Two new BODIPY-fluorene-fullerene (3) and BODIPY-fluorene-BODIPY (4) conjugates were designed, synthesized, and characterized for the first time. The structural properties of compounds were investigated with elemental analysis, mass, ¹H, and ¹³C NMR techniques. Absorption and fluorescence spectroscopy were used to examine the photophysical (absorption and emission profiles, fluorescence quantum yields, and lifetimes) and photochemical (formation of singlet oxygen (¹O₂)) properties. It was observed that the novel compounds (3) and (4) showed high molar extinction coefficients and good ¹O₂ quantum yields. ¹O₂ formation ability of the BODIPY-fluorene-fullerene conjugate (3) was more efficient than that of the BODIPY-fluorene-BODIPY conjugate (4). Furthermore, photosensitization ability of both conjugate systems was more remarkable than some commonly used BODIPY based photosensitizers. The data presented in this work indicate that these two novel systems are effective ¹O₂ photosensitizers that might be used for various areas of applications such as photodynamic therapy and photocatalysis.