The synthesis and fluorescence properties of novel 1,8-naphthalimide derivatives

Three novel 1,8-naphthalimide derivatives containing indole and indoline were synthesized through Fischer indole synthesis, reduction, and alkylation. Two reference dyes with similar structures to the three novel dyes were also prepared. The absorption and fluorescence spectra of these dyes in a variety of solvents were investigated. In addition, fluorescence of these dyes in solid state was also measured. Intramolecular charge transfer was confirmed within the new dyes by virtue of shifts in emission maximum with increasing solvent polarity. Intermolecular close contacts and lateral intermolecular hydrogen bonding interactions between neighboring columns lead to fluorescence wavelength shift, short in the solution and long in the solid state.