Step‐Mediated Anisotropic Adsorption and Condensation of tert‐Butylamine on Cu(111)

Abstract

Scanning tunneling microscopy (STM) combined with density functional theory (DFT) calculations were applied in studying the anisotropic adsorption and condensation of tert-butylamine (t-BA) molecules in the vicinity of the steps on the Cu(111) surface. The preferential adsorption at the upper step edges and uneven distribution of t-BA in the vicinity of the steps illustrate the asymmetric electronic structure of the surface steps. Our observation demonstrates that the adsorption and diffusion of a polar molecule would be significantly mediated by steps on metal surfaces due to the molecule-step interaction and the intermolecular interactions.

Scanning Tunneling Microscopy Investigation of Substrate-Dependent Adsorption and Assembly of Metallofullerene Gd@C82 on Cu(111) and Cu(100)

“…As reported in previous studies, Gd@C 82 molecules were electrophilic and there was charge transfer from the substrate to the fullerene molecules. 19 Therefore, due to the Smoluchowski effect, 20,21 which creates a charge distribution that leaves the top of the step edge slightly electropositive and the bottom electronegative, the bottom of the step edge was preferred by the Gd@C 82 molecules. In addition, the bottom of the step edge has a higher coordination number than the upper sites and should also be consequently favored.…”

Self-Assembly of N,N′-Di(n-butyl)-1,3,8,10-tetramethylquinacridone Governed by Metallic Surface Features of a Ag(110) Substrate

“…We rationalize that the significant difference of adsorption energy between T­(α) and T­(β) results from distinction of the electronic state between Ag atoms of terraces and steps. In the case of transition-metal surfaces, the undercoordinated step atoms have more localized d-states, which allows greater orbital overlap with the terminal oxygen atom, , and thus, step atoms interact more strongly with organic adsorbates, leading to the commonly higher adsorption energies at atomic steps. − The calculated intermolecular binding energy ( E b ) of T­(β) is −0.03 eV, and this very small binding energy is negligible within the numerical uncertainty of the DFT calculations, indicating that there is no effective interaction between molecules along the step edges in T­(β). Therefore, the formation of T­(β) is driven by the strong interaction between the steps and TMDBQA molecules, and the created coordinative covalent bonds stabilize facets and direct the orientation of the molecules with respect to the steps.…”

Supramolecular Anisotropy in a Surface-Confined Bicomponent System

“…Anisotropical engineering of supramolecules is of interest due to its potential in achieving unique properties and high performance of molecular nanomaterials . For instance, the anisotropies in optical properties, dielectrics, electrical conductivity, and the likes of the molecular systems have been realized by anisotropic supramolecular ordering, which plays critical roles in a variety of applications such as liquid crystal display, molecular electronics, electromagnetic wave adsorption, and so on. − Structural anisotropy at the supramolecular level in a surface-confined system can be realized by utilization of either the anisotropically functionalized molecular building blocks ,,, or the substrate with anisotropic surface structures (e.g.,, vicinal surfaces). ,− The orientation-dependent structures of the molecular building blocks and/or substrate surfaces would lead to discriminative energies for the supramolecular structures to grow along different directions, which facilitates the emergence of supramolecular anisotropy. In this context, it is difficult to construct anisotropic supramolecular structures with highly symmetric molecular building blocks on the low-Miller-index surfaces, which would not only simplify the design of the supramolecular systems but also enrich the diversity of the resultant anisotropic supramolecules.…”