Effects of regioisomeric BODIPY-C60 bis-cycloadducts on the generation of singlet oxygen

Abstract

In this study, the first examples of bis-adduct BODIPY-C₆₀ derivatives bearing glucose moieties as targeting unit were synthesized as heavy-atom-free triplet photosensitizers. Synthesized molecules were characterized via mass, ¹H and ¹³C NMR spectroscopy techniques. UV-vis absorption and fluorescence emission spectroscopies were used to determine the photophysical properties of the developed photosensitizers. Singlet oxygen generation (¹O₂) capacities of the bis-adduct BDP-C₆₀-1 and BDP-C₆₀-2 dyads were investigated via both direct and indirect methods in organic solvents, whereas the singlet oxygen quantum yields were calculated as 60% for BDP-C₆₀-1 and 55% for BDP-C₆₀-2. The dyads were also used as heavy-atom-free triplet photosensitizers for the photooxidation of ABDA via the photosensitizing of ¹O₂ in aqueous media. Hence, it was determined that the new triplet photosensitizers were quite capable of generating singlet oxygen in both dichloromethane and aqueous media. The results are compared to those of the mono-adduct BODIPY-fullerene dyad systems.