Synthesis and photochemical characteristics of novel tribenzoporphyrazines possessing peripherally annulated tetrahydrodiazepine and diazepine rings

Novel tribenzoporphyrazines possessing peripherally annulated tetrahydrodiazepine and diazepine rings were synthesized and characterized, and the substituent effects on their absorption spectra in various solvents and on singlet oxygen generation were studied. Solvatochromic effects of tribenzoporphyrazines dissolved in a range of protic and aprotic solvents were evaluated by monitoring the changes in the UV–Vis spectra. The correlation between the Q-band shift towards longer wavelengths and the refractive index of the solvent indicated that the solvatochromic effects are mainly a result of solvation rather than coordination processes. The potential photosensitizing activity of novel tribenzoporphyrazines was evaluated by measuring the ability of singlet oxygen production, which is the result of the interaction between an activated photosensitizer and oxygen. This experiment proves promising photosensitizing activity of novel styryldiazepinotribenzoporphyrazine, which is an efficient singlet oxygen generator with a ΦΔ value of 0.44, although this value is a little lower than that of zinc phthalocyanine.

Novel tribenzoporphyrazines possessing peripherally annulated tetrahydrodiazepine and diazepine rings were synthesized and characterized, and the substituent effects on their absorption spectra in various solvents and on singlet oxygen generation were studied.Figure optionsDownload as PowerPoint slideResearch highlights
► Novel tribenzoporphyrazines possessing peripherally annulated tetrahydrodiazepine and diazepine rings were synthesized and characterized.
► The substituent effects on their absorption spectra in various solvents and on singlet oxygen generation were studied.
► The correlation between the Q-band shift towards longer wavelengths and the refractive index of the solvent indicated that solvatochromic effects are mainly a result of solvation rather than coordination processes.
► Promising photosensitizing activity of the novel styryldiazepinotribenzoporphyrazine was found, with a ΦΔ value of 0.44.