Bridging the Bays, Both Ways: A Janus Butterfly-Shaped Intense NIR-Emitting Terrylene Diimide

Molecules with intense near-IR (NIR) emission are beneficial for modern applications such as night vision, bio-imaging etc. However, elaborate synthetic manipulations make them demanding to accomplish. Herein, we present a simple yet exciting strategy to obtain novel Janus butterfly-shaped terrylene diimide derivatives with carbazole wings having absorption and intense emission in the NIR. Especially, unsymmetrically substituted terrylene diimides (TDIs) have been observed to have impressive emission quantum yields (up to 93 %), highest for this class of compounds. Minimal structural distortion as evidenced from structural characterization has been shown to correlate with these observations. Also, a novel two-tiered TDI-carbazole having an intense emission at 897 nm is also reported. Our strategy demonstrates that efficient near-IR luminophores can be achieved via precise functionalization.

Automated summary

This article presents a simple and exciting strategy to synthesize novel terrylene diimide derivatives with absorption and intense emission in the near-IR through precise functionalization. The symmetrically substituted terrylene diimides show impressive emission quantum yields, and minimal structural distortion is found to be correlated with the emission characteristics. Additionally, a two-tiered TDI-carbazole compound with intense emission in the near-IR is reported.