Pentarylene- and Hexarylenebis(dicarboximide)s: Near-Infrared-Absorbing Polyaromatic Dyes

摘要

Although a large variety of dyes are commercially available today, there is an ongoing need for new chromophoric systems and low-band-gap materials. For example, near-infrared (NIR) emission has received increased attention for applications in bioassays and medicine while NIR absorption is demanded for laser-welding of plastics or efficient blocking of heat rays. Most of the commercially available NIR materials are not suitable for such purposes owing to their insufficient stability. Over the last decade we have developed several NIR-absorbing polyaromatic dyes. By extending the system of perylenebis(dicarboximide)s along the molecular long axis, we have obtained the higher homologues terrylenebis(dicarboximide) (2) and quaterrylenebis(dicarboximide) (3; Figure 1). In comparison to the absorption maximum of perylenebis(dicarboximide) (1), those of 2 and 3 are shifted bathochromically. Quaterrylenebis(dicarboximide) (3) is a deeply colored dye with a strong absorption in the NIR region. Both chromophores exhibit high thermal, chemical, and photochemical stabilities together with high extinction coefficients. Recently we introduced an alternative and surprisingly facile approach toward NIR absorbers by the coupling and fusion of a perylenedicarboximide with a 1,5-diaminoanthraquinone to afford bis(perylenedicarboximide)-a,d-1,5-diaminoanthraquinone (4), a NIR absorber with a remarkably strong absorption around 1100 nm and extraordinary thermal and photochemical inertness.