Externally Applied Manipulation of Molecular Assemblies at Solid‐Liquid Interfaces Revealed by Scanning Tunneling Microscopy

Abstract

A solid-liquid interface is a unique environment for the construction of twodimensional molecular assemblies as a bottom-up approach towards functional surfaces. Scanning tunneling microscopy (STM) has proven itself as an excellent tool to characterize such surfaces at the molecular level, by means of visualization. Many rules of design for surface, solvent and chemical structure of the adsorbants have been established, but methods to externally manipulate surface assemblies after their formation are still under development. This feature article deals with these manipulation methods at the solid-liquid interface and evaluates, at the molecular level, the effects of temperature variation, irradiation with light, applied electric or magnetic fields, mechanical manipulation with the STM tip, and shear flow of the liquid phase.

Dynamic host–guest behavior in halogen-bonded two-dimensional molecular networks investigated by scanning tunneling microscopy at the solid/liquid interface

“…[11][12][13][14][15] Previously, supramolecularly engineered 2D structures in physisorbed monolayers at solid/liquid interfaces have been investigated by scanning tunneling microscopy (STM) with submolecular resolution. [16][17][18][19][20][21][22][23] The formation of 2D structures at the solid/liquid interface is affected by several parameters such as the solvent type, temperature, concentration, alkyl chain length, intermolecular interactions, and electric eld. By tuning these parameters, a wide variety of 2D network structures have been constructed.…”

“…By tuning these parameters, a wide variety of 2D network structures have been constructed. [16][17][18][19][20][21][22][23] The 2D porous networks of supramolecular assemblies have attracted much attention because they can capture and immobilize guest molecules in their pores, and they are potentially applicable in molecular devices, nanoelectronics, sensors, catalysis, etc. [24][25][26][27][28][29][30][31][32][33][34] There have been many remarkable studies on the host-guest chemistry at surfaces accommodating guest molecules such as coronene and fullerene, allowing the construction of multi-component molecular assemblies.…”

Imine‐Based Architectures at Surfaces and Interfaces: From Self‐Assembly to Dynamic Covalent Chemistry in 2D

“…[1,2] It is worth noting that DCC shares variousf eatures with supramolecular chemistry;i np articular, they both rely on reversible bonds that enable the formation of complex structures and materials under thermodynamic control. [10] Whereas classical covalent chemistry operates under kinetic control,t he DCC approacht akes advantage of the reversible natureo fb ond formation to generate new covalent structures under thermodynamic control. However,t here are some major differences between these two types of reversible chemical approaches.…”

“…This variable range of parameters allows one to designa nd create compounds that can adjust to their environment. [10] Whereas classical covalent chemistry operates under kinetic control,t he DCC approacht akes advantage of the reversible natureo fb ond formation to generate new covalent structures under thermodynamic control. [11] In particular,D CC includes the chemistry of disulfides, [12,13] acetals, [14,15] esters, [16,17] oxime, [18] boroxine, [19,20] alkynes, [21] and imines [22][23][24][25][26][27][28][29] to allow the generation of new covalents tructures.…”

“…In DCC, both internal and external factors, such as concentration, temperature, pressure, or the presence of impurities, can have a significant effect on the equilibrium and distribution of products, even after the formation of the targeted product. This variable range of parameters allows one to design and create compounds that can adjust to their environment …”