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Abstract:
The molecules of discotic liquid crystals consist of disc-like cores to which flexible side chains are linked at the periphery [1]. In most cases the cores consist of flat medium size aromatic moieties, such as benzene, naphthalene and triphenylene, but more recently discogens with much larger cores, such as hexabenzocoronene have also been prepared [2, 3]. The side chains are usually normal aliphatic groups, which are linked to the core by ether or ester bridges, but there are many other modifications including heteroatoms or even direct carbon-carbon bonds. They serve as “lubricants” for the planar reorientation of the molecules. Discotic mesogens usually form columnar mesophases, although nematic and lamellar discotic phases are also known. The columnar phases may be regarded as one-dimensional liquids, being ordered in the transverse plane of the lattice and liquid-like along the column direction. Usually the center cores of the discogens are rigid and flat, however flexible, non- planar cores are also known. These are in most cases macrocyclic moieties, such as ortho- or meta- cyclophanes [4, 5]. In the present work we discuss columnar mesophases derived from a lower homologue of the orthocyclophane, i. e. tribenzocyclononatriene (TBCN)
