Structural Phases of Ordered FePc-Nanochains Self-Assembled on Au(110)

Iron-phthalocyanine molecules deposited on the Au(110)
reconstructed channels assemble into one-dimensional molecular chains,
whose spatial distribution evolves into different structural phases at increasing
molecular density. The plasticity of the Au channelsfirst induces an ordered
phase with a 5×5 symmetry, followed by a second long-range ordered
structure composed by denser chains with a 5×7 periodicity with respect to the
bare Au surface, as observed in the low-energy electron-diffraction (LEED)
and grazing incidence X-ray diffraction (GIXRD) patterns. The geometry of
the FePc molecular assemblies in the Au nanorails is determined by scanning
tunneling microscopy (STM). For the 5×7 phases, the GIXRD analysis
identifies a“4-3”rows profile along the [001] direction in the Au surface and
an on-top FePc adsorption site, further confirmed by density functional theory
(DFT) calculations. The latter also reveals the electronic mixing of the
interface states. The chain assembly is driven by the molecule−molecule
interaction and the chains interact with the Au nanorails via the central metal atom, while the chain−chain distance in the
different structural phases is primarily driven by the plasticity of the Au surface.