A two-step synthesis of quaterrylenetetracarboxylic bisimides-novel NIR fluorescent dyes

Article abstract of DOI:10.1016/0040-4039(95)01276-N

Quaterrylenetetracarboxylic bisimides are prepared from perylene-3,4:9, 10-tetracarboxylic bisanhydride via perylene-3,4-dicarboxylic imides which are dimerized in molten alkali. The unsubstituted bisimide is an insoluble black pigment. N-substitution with the solubility-increasing 1-hexylheptyl group gives a soluble dye with a remarkably strong fluorescence in the NIR region (816 nm).