Facile Synthesis and Phase Behaviors of Monofunctionalized Hexa-peri-hexabenzocoronenes

Abstract

Five different kinds of monofunctionalized hexa-peri-hexabenzocoronenes (HBCs) are synthesized by loading dialkyl-diphenylacetylenes and asymmetric diphenylacetylene derivatives at the same time. This method shortens the synthetic route by half, with four fewer steps compared with the commonly used approach. In addition, this method is more economic and environmentally friendly. The self-assembling properties of the molecules are greatly influenced by the substituted alkyl side chains. From the short linear hexyl chain (C6) to the longer n-dodecyl (C12) chain and then to the branched alkyl chain (C10,6), the transition temperature from the crystalline phase to the liquid crystalline (LC) phase and that from the LC phase to the isotropic (Iso) state both decrease. Furthermore, the ester group far away from the aromatic core and its length are also important variables to control the phase behaviors of the molecules. The typical long-range ordered hexagonal lattice (Colh phase) is found for all the monofunctionalized molecules in their LC states.