Columnar Mesophases from Nondiscoid Metallomesogens:  Rhodium and Iridium Dicarbonyl Diketonates

A series of nondiscoid rhodium and iridium dicarbonyl β-diketonate complexes have been shown to organize in columnar liquid crystal phases with hexagonal disordered structures (Col hd ). The shape and dipolar attributes of these materials produce highly correlated antiparallel pairwise arrangements. This organization was investigated by X-ray diffraction and miscibility studies. The liquid crystallinity was found to be stabilized by decreasing the number of carbon atoms in the side chains, and single component room-temperature liquid crystals were developed. The nature of the metal is also important, and iridium mesogens exhibited higher clearing points than the analogous rhodium materials.