DISCOTIC LIQUID-CRYSTALS THROUGH MOLECULAR SELF-ASSEMBLY

We have created self-assembled disk-like aggregates of predictable sto ichiometry which form discotic liquid crystalline phases. Attempts to assemble multiple molecules of one compound radially about a second ac ting as a template failed, presumably owing to the existence of a stab le crystalline phase of the template. This difficulty was obviated by the choice of tetrakis(n-alkoxy)-6(SH)-phenanthridinon (1a-c), which w ere expected to form disk-like dimers by analogy with pyridones. All t hree of these compounds form columnar hexagonal liquid crystalline pha ses as shown by DSC, POM, and X-ray diffraction experiments. Infrared measurements show that la-e exist as hydrogen-bonded aggregates to tem peratures well above their clearing points. Intercolumnar spacing and density considerations require the discotic entities to be dimers.