Photosensitizing Properties of 6H ‐Dibenzo[ b, h ]xanthene Derivatives

Abstract Dibenzoxanthenes are a class of compounds that have attracted attention due principally to their photochemical and photophysical properties. The absorption spectra of the dibenzo[ b, h ]xanthene derivatives revealed a blue shift in the absorption spectra on increasing the solvent polarity. The laser flash photolysis technique was used to study the reactivity of the triplet excited states of the dibenzo[ b, h ]xanthene‐5,6,8,13‐tetrone derivatives. Hydrogen atom or electron donors, including model biological compounds, led to quenching of the excited state and formation of a new transient, thus revealing type I photosensitizer reactivity. Further, energy transfer to oxygen to generate singlet oxygen was also observed demonstrating type II photosensitization. Additionally, the novel dibenzo[ b, h ]xanthene‐5,6,8,13‐tetrol acetates revealed fluorescence emission with maximum wavelengths between 350–360 nm.