Synthesis of Three-Dimensional Butterfly Slit-Cyclobisazaanthracenes and Hydrazinobisanthenes through One-Step Cyclodimerization and Their Properties.

New three-dimensional (3D) π-conjugated molecules, butterfly-shaped slit-cyclobisazaanthracenes, were synthesized in high yields by Ni-mediated one-step cyclodimerization of dibromoazaanthracenes with a dimethylacridine, phenothiazine, or acridone skeleton. The 3D slit butterfly shape was formed by folded azaanthracene skeletons. Closure of the slit via NN bond formation afforded hydrazinobisanthenes with an embedded hydrazine structure in a bisanthene skeleton, which exhibited a 3D butterfly or a 2D plane structure depending on the type of heterocycle used. Extensive study of the stereoselective chemical reactivity of the butterfly shape, X-ray analysis, DFT calculations, electrochemical/chemical oxidations, and photophysical measurements revealed that the properties of these materials included stereoselective oxidation, a rigid or flexible butterfly shape, dynamic conformational behavior, unique crystal-packing structures, excellent electron donation with low oxidation potential, a radical cation, a long absorption wavelength, and fluorescence property.