Self-assembly of chiral molecular honeycomb networks on Au(111)

Self-assembly of the specifically designed 3-fold symmetric 1,3,5-trikis(4′-carboxylphenyl)-2,4,6-trikis(4′-tert-butylphenyl)-benzene molecule on a Au(111) surface is investigated by means of in situ ultrahigh vacuum scanning tunneling microscopy. A variety of chiral honeycomb networks with increasing interpore distance is observed. Experiments and force field calculations reveal that the formation of the two-dimensional hexagonal porous networks is driven by a balance of molecular close-packing within half-unit cells and cyclic hydrogen bonding dimerization between half-unit cells. The honeycomb networks are shown to be chiral owing to asymmetric molecular close-packing within the half-unit cells.