1,6-Disubstituted perylene bisimides: concise synthesis and characterization as near-infrared fluorescent dyes

Detailed studies on bromination and subsequent imidization of perylene bisanhydride were reported. 1,6,7,12-Tetrabromoperylene bisimide was obtained in an optimized high yield. In addition, 1,6-disubstituted regioisomer was separated for the first time in isomerically pure form, and the structure was confirmed by 1H NMR, MS, element analysis, and photophysical measurements. By using a mixture of regioisomers 1,6- and 1,7-dibromo-perylene bisimide, 1,6-dipiperidinylperylene bisimides (1,6-Piper-Pery) were synthesized, purified, and their fluorescence were measured with a peak at 760 nm. These compounds can be used as stable near-infrared absorbing and fluorescent dyes.