Light-driven molecular motors embedded in covalent organic frameworks.

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Integrating molecular machines into porous frameworks offers potential for nano actuation and controlled molecular transport.
• Covalent Organic Frameworks (COFs) are crystalline porous materials with tunable structures and properties.

Purpose of the Study:

• To synthesize and incorporate a light-driven molecular motor into imine-based polymers and COFs.
• To investigate the structural, dynamic, and supramolecular properties of these novel motorized porous materials.

Main Methods:

• Synthesis of a diamine-based light-driven molecular motor.
• Incorporation of the motor into imine-based polymers and covalent organic frameworks (COFs) via acid-catalyzed synthesis.
• Characterization using spectroscopic, diffraction, and theoretical methods, including in situ spectroscopy.

Main Results:

• Successful synthesis of the first crystalline 2D COF containing 20 mol% molecular motors with specific pore volume (0.45 cm³ g⁻¹) and surface area (604 m² g⁻¹).
• Detailed study of supramolecular assembly and stacking disorders due to the motor's structure.
• In situ spectroscopic analysis revealed motor dynamics and highlighted current analytical limitations.

Conclusions:

• Demonstrated the feasibility of creating motorized porous framework materials.
• Provided critical analysis and design criteria for future generations of these advanced materials.
• Opened avenues for out-of-equilibrium host-guest chemistry in solid-state materials.