1,7‐Difluorophore‐Substituted AzaBODIPYs

Abstract

Four different 1,7‐disubstituted azaBODIPYs containing fluorophores such as naphthalene, anthracene, and pyrene were synthesized over multiple steps involving aldol condensation, Michael addition, dipyrromethene formation, and BF2 complexation. All of these steps were optimized, and the target 1,7‐difluoro‐substituted azaBODIPYs along with other intermediate compounds were thoroughly characterized by HRMS and 1D and 2D NMR spectroscopy. Absorption and electrochemical studies indicated a strong interaction between the fluorophores and the azaBODIPY moieties in compounds 1–4. Fluorescence studies revealed that 1,7‐disubstituted azaBODIPYs with naphthalene and pyrene fluorophores were fluorescent and that singlet–singlet energy transfer from the fluorophores to the azaBODIPY moiety was possible, whereas 1,7‐dianthracenyl‐substituted azaBODIPY was completely nonfluorescent owing to efficient photoinduced electron transfer between the anthracene and azaBODIPY moieties.