Two-Dimensional Self-Assembly of Dendritic Amphiphilic Molecule with Ferroncenyl Subsitutuents at the Liquid/Solid Interface

Two-dimensional self-assembly of dendritic amphiphilic molecule with ferroncenyl subsitutuents (2,3,4-tri-(11-ferroncenyl)undecyloxybenzoic acid, Fc(3)COOH) on highly oriented pyrolytic graphite surface was investigated by scanning tunneling microscopy at the liquid/solid interface. Fc(3)COOH molecule formed an ordered molecular nanostructure an alternating big/small bright dots pattern on the graphite surface extended to several hundred nanometers. On the basis of the simulation and combined with our STM results, it is concluded that the molecular adsorption conformation has an appreciable effect on the interactions of molecule-molecule and molecule-substrate. The pi-pi interactions between ferrocene groups together with the van der Waals interactions between alkyl chains direct the stacking behavior of Fc(3)COOH molecules. Due to the steric constraints, no hydrogen bonding between the carboxyl groups was formed during the self-assembly.