Triphenanthro‐anellierte [18]Annulene mit Alkoxy‐Seitenketten — Eine neue Klasse discotischer Flüssigkristalle

Abstract

Triphenanthro‐Anellated [18]Annulenes with Alkoxy Side Chains ‐ A Novel Class of Discotic Liquid Crystals Two different types 6 and 16 of [18]annulenes condensed with phenanthrene systems were prepared by cyclocondensation reactions (Schemes 2 and 3). The central 18‐membered rings do not show a macrocyclic diamagnetic ring current. Conformational analyses and X‐ray analyses in the solid state reveal non‐planar structures in which aromatic “islands” are connected by (E)‐configurated olefinic bridges. The introduction of long alkoxy side chains yields a new class of discotic liquid crystals; either ND or hexagonal columnar phases are generated, which were characterized by DSC, microscopy with polarized light, and small‐angle scanning X‐ray.

Star‐Shaped Compounds Having 1,3,5‐Triazine Cores

“…Identification by comparison with an authentic sample. [30,38] Preparation of the aldehydes 11aϪd was performed according to the literature: 11a, [45,46] 11bϪd. [30] General 2-[3,4 2-(4-{(E)-2-[3,4,5-tris(hexyloxy) After vigorous stirring for 30 min, the reaction mixture was kept at room temperature overnight.…”

Synthesis of Tripyreno[2,3,4-abc: 2,3,4-ghi: 2,3,4-mno][18]annulenes

“…Yield 8.1 g (70%), almost colourless oil. The yield obtained with this modified procedure was about twice as high as in the original procedure [11]. The product was identified by comparison with an authentic sample [11].…”

“…In contrast to the unsubstituted [18]annulene [21], the areno-condensed [18]annulenes are not planar [4,6,11]. They can be regarded as aromatic "islands" which are combined by trans configured olefinic "bridges".…”

“…The data presented below refer to the pure (E)-configuration. 4 Preparation according to the literature [11]. The product was identified by comparison with an authentic sample.…”

“…Many areno-condensed annulenes exhibit a high tendency of aggregation in solution as well as in the neat phase [4,6,7,8,11]. Thus, bimolecular photoreactions are efficient even in highly diluted solutions, because light is being absorbed by aggregates (dimers etc.).…”