Supramolecular Control of Two‐Dimensional Phase Behavior

Abstract

We have used directed two‐component self‐assembly to “pattern” organic monolayers on the nanometer scale at the liquid/solid interface. The ability of the scanning tunneling microscope to investigate structural details in these adlayers was used to gain insight into the two‐component two‐dimensional phase behavior. The components are symmetrically alkylated bisurea derivatives (R1‐urea‐spacer‐urea‐R2; R1, R2=alkyl, spacer=alkyl or bisthiophene). The bisthiophene unit acts as a marker and its bisurea derivative (T2) is a component in all the mixtures investigated. By varying the position of the hydrogen‐bond forming urea groups along the molecule and the length of the alkyl chains of the other components, the effect of 1) hydrogen bonding, 2) molecule length, 3) odd–even effects, and 4) shape complementarity on the two‐dimensional phase behavior was investigated. Insight into the effect of these parameters leads to the control of the two‐dimensional patterning: from randomly intermixed systems to phase separation.

Aggregation and Contingent Metal/Surface Reactivity of 1,3,8,10‐Tetraazaperopyrene (TAPP) on Cu(111)

“…[9] It is the balance between intermolecular and molecule-surface interactions, the reversibility or irreversibility of intermolecular bond formation and the resulting availability or non-availability of structural repair mechanisms that governs the detailed structures and longrange order of molecular surface assemblies. [10] Whereas weak intermolecular interactions such as vdW forces and hydrogen bonding have been shown to lead to molecular arrays characterised by high levels of long-range order and tunable structural characteristics [11] such as porosity, [12] their generally observed thermal instability limits this approach in the fabrication of hierarchically assembled aggregates. Surface coordination networks obtained either by combination of organic ligands with adatoms of the substrate or by their reaction with vapour-deposited heterometal atoms possess greater inherent stability.…”

Self-assembly of tetraalkoxydinaphthophenazines in monolayers on HOPG by scanning tunneling microscopy

“…It is therefore a question of fundamental importance to determine the influence of the number, length and position of these substituents on the spontaneous organization of molecules. STM techniques have been frequently used for such investigations in monolayers of organic molecules of very different chemical natures, for example alkyl (alkoxy) derivatives of: benzoic acids [18], thiophene [15,16,[19][20][21][22], annulene [23,24], fluorenone [25,26], stilbene [27], and others [28][29][30][31].…”

Two‐Dimensional Aggregation of Organogelators Induced by Biaxial Hydrogen‐Bonding Gives Supramolecular Nanosheets

“…[10][11][12][13][14][15][16][17][18][19][20] However, 2D organization of bis-urea derivatives at solution/ graphite interfaces has been studied. [21] In the current study, bis-acylurea derivatives, BUC5BU and BUC6BU (Fig. 1a) were obtained by reacting butyl urea with pimeloyl chloride and suberoyl chloride, respectively in the presence of pyridine.…”