Anthra- and pentacenequinone derivatives: influence of structure on the formation of columnar liquid crystal phases

We report the synthesis and mesophase characterization of a series of novel di- and tetra-aryl acenequinones. Diphenyl-acenequinones 1 and 2 exhibit monotropic mesophases while tetra-aryl acenequinones 4 and 5 exhibit stable columnar hexagonal mesophases. Compound 4 exhibits a more stable columnar mesophase than 5 , consistent with a packing motif where molecules are stacked in perpendicular arrangement. The mesomorphic properties of novel acenequinones reveals that a perpendicular packing motif is an important factor for determining mesophase stability.