Tuning Molecular Packing and Boosting Self-Assembling Properties via Ring Fusion Strategy in Naphthalimide-Based A-D-A Conjugated Systems.

Two fully fused acceptor-donor-acceptor (A-D-A) architecture conjugated derivatives ( NPF and NCF ) comprising an electron-withdrawing naphthalimide (NMI) and two different electron-donating cores, phenanthrene and carbazole, respectively, were conveniently synthesized by bismuth(III)-catalyzed selective cyclization of vinyl ethers. Compared with their corresponding single bond-linked A-D-A molecules NPS and NCS , both having a moderately twisted aromatic configuration, the ring fusion strategy leads to fully coplanar conjugated skeletons and greatly changes the electronic structures, photophysical properties, self-assembling behaviors, and molecular packing motifs. In particular, the naphthalimide/carbazole derivative NCF exhibits intriguing 2D brickwork packing and significantly enhanced self-assembling properties.