2,3 : 6,7-Naphthalenediimide-Based Chiral Triangular Macrocycle: Self-Assembled Helix, Outer π-Surface Directed Co-Assembly and Circularly Polarized Luminescence

Here, we report the synthesis and self-assembly of a novel chiral 2,3 : 6,7-naphthalenediimide-based triangular macrocycle (NDI-Δ) and its chiroptical properties. The enantiomeric NDI-Δ is synthesized by condensation of (RR) or (SS)-trans-1,2-cyclohexanediamine and 2,3,6,7-naphthalenetetracarboxylic 2,3 : 6,7-dianhydride, in which the chirality of the macrocycles is controlled by the diamine. With the rigid outer π-surface, the macrocycle exhibits unique chiroptical properties and self-assembly modes. The NDI-Δ shows circularly polarized luminescence (CPL) in solution and can self-assemble into helical structures with the inversion of CPL signal and the enhancement of |g_lum|. Moreover, the NDI-Δ has a tailored electron-deficient outer π-surface, which can co-assemble with an electron-rich anthracene (AN) to form an intermolecular charge transfer (CT) complex, generating a yellow-green CT-CPL. Crystal structure analysis confirms that AN is mounted on the outer surface of NDI-Δ through π-π stacking and C-H $\cdots$ π interactions. This work provides a critical example for the self-assembly of macrocycles into helical structures and outer π-surface directed CT complexes formation, opening up a new clue for designing chiral macrocycle-based chiroptical materials.