TRIPHENANTHRO-ANELLATED [18]ANNULENES WIT H ALKOXY SIDE-CHAINS - A NOVEL CLASS OF DISCOTIC LIQUID-CRYSTALS

Two different types 6 and 16 of [18]annulenes condensed with phenanthr ene systems were prepared by cyclocondensation reactions (Schemes 2 an d 3). The central 18-membered rings do not show a macrocyclic diamagne tic ring current. Conformational analyses and X-ray analyses in the so lid state reveal non-planar structures in which aromatic ''islands'' a re connected by (E)-configurated olefinic bridges. The introduction of long alkoxy side chains yields a new class of discotic liquid crystal s; either ND or hexagonal columnar phases are generated, which were ch aracterized by DSC, microscopy with polarized light, and small-angle s canning X-ray.