Supramolecular staircase via self-assembly of disklike molecules at the solid-liquid interface.

摘要: A series of soluble hexabenzocoronene (HBC) derivatives with pendant optically active (S)-3,7-dimethyloctanyl and (R,S)-3,7-dimethyloctanyl (mixture stereoisomers) hydrocarbon side chains without a phenylene spacer were assembled into differently ordered arrays at the interface between solution basal plane highly oriented pyrolytic graphite (HOPG). Molecularly resolved scanning tunneling microscopy (STM) images revealed that all self-assemble crystals in quasi-two dimensions. However, while for alkyl-substituted HBCs (1,4) single aromatic cores within monolayer exhibit same contrast STM, group alkyl core (2a,2b,3) different contrasts monolayer. For disks carrying racemic branched or n-alkyl (2b,3) random distribution two 2D-crystal is observed, ph...