Highly Ordered Co-Assembly of Bisurea Functionalized Molecular Switches at the Solid-Liquid Interface

Area of Science:

• Surface science
• Supramolecular chemistry
• Nanotechnology

Background:

• Immobilizing stimulus-responsive systems on surfaces is crucial for controlled signal transmission and adaptive behavior.
• Precise positioning of responsive units at the nanoscale is a key challenge for cooperative function.
• Bridging molecular and macroscopic worlds requires advances in nanoscale organization, cooperativity, and amplification.

Purpose of the Study:

• To design, synthesize, and characterize overcrowded alkene photoswitches within self-assembled networks on solid surfaces.
• To develop an anchoring strategy for controlled orientation of photoswitches using bis-urea groups.
• To establish guidelines for precise photoswitch organization in crystalline physisorbed self-assembled molecular networks.

Main Methods:

• Scanning tunneling microscopy (STM) for (sub)molecular resolution characterization.
• Co-assembly strategy merging photoswitches with spacer molecules in physisorbed monolayers.
• Molecular mechanics (MM) simulations to support experimental data.

Main Results:

• Robust immobilization and controlled orientation of photoswitches within spacer monolayers confirmed by STM.
• Successful co-assembly of photoswitches and spacers into ordered molecular networks.
• Experimental data validated by molecular mechanics simulations.

Conclusions:

• Developed a method for precise nanoscale organization of photoswitches on solid surfaces.
• Demonstrated the utility of bis-urea anchoring groups and co-assembly strategies.
• Provided guidelines for designing photoswitch-based self-assembled molecular networks for advanced applications.