Columnar Liquid-Crystalline Macrocycles Synthesized via Metal Ion-Assisted Self-Assembly.

Columnar assemblies of liquid-crystalline (LC) macrocycles hold promise for the construction of nanochannels in fluid materials. Metal-assisted self-assembly is an efficient way to prepare LC macrocycles. A large π-conjugated ligand, 9,10-diphenylanthracene (DPA) bearing two β-diketones, was prepared as a building unit for the macrocycle, and a series of side chains were incorporated into the DPA to yield LC materials. The bis(β-diketone) ligands on DPA allow for the efficient formation of triangular 3:3 metallomacrocycles in the presence of square-planar Cu2+ ions. The copper-containing 3:3 metallomacrocycle with the appropriate side chains exhibited thermotropic columnar LC phases in which the columns were arranged in rectangular arrays over a wide temperature range, and well-ordered birefringent textures were observed under a polarized microscope.