Photophysical properties of 1,3,6,8-tetrakis(arylethynyl)pyrenes with donor or acceptor substituents: their fluorescence solvatochromism and lightfastness

We prepared a series of 1,3,6,8-tetrakis(arylethynyl)pyrenes with donor or acceptor substituents and investigated their photophysical properties. Solvent polarity hardly affected on the UV/vis spectra of all of the tetrakis(arylethynyl)pyrenes used in this study. On the other hand, electron-donating groups, NMe2 and NPh2 groups imparted fluorescence solvatochromicity to the skeleton by intramolecular charge transfer in the excited state. Furthermore, a tetrakis(arylethynyl)pyrene showed better lightfastness upon exposure to laboratory weathering using a xenon long arc lamp than coumarin.