Discotic Liquid Crystals through Molecular Self-Assembly

We have created self-assembled disk-like aggregates of predictable stoichiometry which form discotic liquid crystalline phases. Attempts to assemble multiple molecules of one compound radially about a second acting as a template failed, presumably owing to the existence of a stable crystalline phase of the template. This difficulty was obviated by the choice of tetrakis( n -alkoxy)-6(5 H )-phenanthridinones ( 1a−c ), which were expected to form disk-like dimers by analogy with pyridones. All three of these compounds form columnar hexagonal liquid crystalline phases as shown by DSC, POM, and X-ray diffraction experiments. Infrared measurements show that 1a−c exist as hydrogen-bonded aggregates to temperatures well above their clearing points. Intercolumnar spacing and density considerations require the discotic entities to be dimers.