J-type aggregates of a uracil-functionalized aza-bodipy dye directed by hydrogen bonding

J-aggregates of functional dyes represent a class of important supramolecular material that have been applied widely in various fields. A novel boron-azadipyrromethene (aza-BODIPY) dye 1 appended with uracil groups on 2,6-positions was synthesized, which could self-assemble into nanofibrous J-aggregates in methylcyclohexane driven by intermolecular double hydrogen bonds. The maximum absorption wavelength of the J-aggregates of dye 1 located at 768 nm, which was bathochromically shifted for 47 nm compared with that of the monomers. Temperature / concentration-dependent UV / Vis spectroscopy demonstrated that the formation of J-aggregates of dye 1 followed the cooperative self-assembly mechanism. The morphology and molecular packing structure of J-aggregates were studied by transmission electron microscopy and exciton theory calculation.