Supramolecular Assemblies of 1,4-Benzene Diboronic Acid on KCl(001)

Abstract

The self-assembly of benzene diboronic acid molecules on KCl(001) is investigated at room temperature by means of non-contact Atomic Force Microscopy. When depositing the molecules on the freshly cleaved surface, the molecules self-assemble into an extended twodimensional supramolecular phase driven by H-bonds. Theoretical calculations based on Density Functional Theory show that the cohesion energy of the structure yields almost 1 eV per molecule. In combination with high-resolution structural analysis of the molecular layer and theoretical calculations, it is inferred that the growth of the supramolecular phase is made possible owing to the conformational adaptation of the molecule at the surface, which strengthens the intermolecular H-bonds, while avoiding the intermolecular steric hindrance. This work is the first experimental evidence of an extended H-bonded supramolecular network grown on a bulk insulator at room temperature.

Noncontact AFM and differential reflectance spectroscopy joint analyses of bis-pyrenyl thin films on bulk insulators: Relationship between structural and optical properties

“…The characterization of these interfaces from a structural and an optical point of view down to the molecular scale is challenging and requires analytical methods with high sensitivity in an ultrahigh-vacuum (UHV) environment. On the one hand, scanning probe techniques, such as atomic force microscopy (AFM) in noncontact mode (nc-AFM), can provide access to the structure of the adsorbed molecular layers down to the molecular scale [19][20][21][22][23] and beyond [24][25][26][27][28][29]. The nc-AFM method, particularly on bulk insulators and at room temperature is demanding.…”

Molecular Design and Control Over the Morphology of Self‐Assembled Films on Ionic Substrates

“…[ 16 ] The formation of organic layers on insulators has been achieved in the past by either strengthening the molecule-surface (M-S) interaction by means of appropriate anchoring groups, [ 17,18 ] or by reinforcing the molecule-molecule (M-M) interaction. [ 19,20 ] Several attempts have also been made to infl uence the balance between M-S and M-M interactions. [21][22][23] However, achieving control over structural characteristics of large-scale supramolecular networks, such as e.g., pore size, proved challenging.…”

“…[ 26 ] A second strategy involves educated molecular design. Some molecules are able to form wire structures through π-stacking, [ 27,28 ] other examples include stabilization of the molecular layers via hydrogen bonding, [ 19 ] and a few experiments report on the use of polar groups to enhance adsorption onto ionic substrates. [ 17,29,30 ] However, there is no single set of design criteria for the morphology and stability of such fi lms that can satisfy a wide range of possible applications.…”

Tuning Molecular Self‐Assembly on Bulk Insulator Surfaces by Anchoring of the Organic Building Blocks

“…The stabilizing effect of intermolecular hydrogen bonds has, furthermore, been exploited in a recent study utilizing the unusually strong intermolecular cohesion energy of boronic acid to stabilize a wetting layer on KCl(001) at room temperature 86. In this study, the substrate has been shown to have a marginal influence on the resulting molecular film, illustrating that the strong intermolecular cohesion rather than the molecule‐surface adhesion is responsible for the stabilization of the film.…”