The synthesis and spectroscopic properties of novel, functional fluorescent naphthalimide dyes

A series of novel naphthalimide dyes with amino or hydroxyl functional groups were synthesized by the condensation reaction of 4-bromonaphthalic anhydride with primary amines to form the naphthalimide, followed by regio-selective aromatic nucleophilic substitution in basic media. Four of the dyes were selected as representative compounds for analysis by UV absorption and steady state fluorescence spectroscopy in solvents with different polarity. In addition, fluorescence intensity decays of these dyes in dichloromethane were measured. The results suggest that various combinations of the dyes make good donor–acceptor pairs for energy transfer experiments. To anticipate the application of these dyes in the synthesis of dye-labeled polymers by radical polymerizations, the synthesis of a monomer dye containing a methacrylate ester and a dye containing initiator for ATRP polymerization is described.