Varying molecular interactions by coverage in supramolecular surface chemistry

Area of Science:

• Surface Science
• Physical Chemistry
• Materials Science

Background:

• Benzene-carboxylic acids are important molecules with applications in various fields.
• Understanding their surface interactions is crucial for designing new materials and processes.
• Controlling intermolecular forces, such as coordination and hydrogen bonding, is key to manipulating molecular behavior on surfaces.

Purpose of the Study:

• To investigate the influence of surface coverage on the intermolecular interactions of absorbed benzene-carboxylic acids.
• To demonstrate the transition between coordination and hydrogen bonding interactions.
• To provide insights into the fundamental mechanisms governing molecular self-assembly on surfaces.

Main Methods:

• Utilizing scanning tunnelling microscopy (STM) to visualize molecular arrangements at the nanoscale.
• Employing X-ray photoemission spectroscopy (XPS) to analyze surface composition and chemical states.
• Performing density functional theory (DFT) calculations to model and understand the electronic interactions.

Main Results:

• Surface coverage was found to be a critical factor in determining the type of intermolecular interaction.
• A transition from coordination bonds to hydrogen bonds was observed as surface coverage changed.
• Experimental and computational results consistently supported the proposed interaction modification.

Conclusions:

• The intermolecular interactions of absorbed benzene-carboxylic acids can be controllably modified by adjusting surface coverage.
• This control allows for tuning molecular assembly and surface properties.
• The findings offer a pathway for designing surfaces with tailored molecular interactions.