Self-assembly of lattices with high structural complexity from a geometrically simple molecule

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Crystal Engineering

Background:

• Designing complex porous materials often requires intricate molecular building blocks.
• Achieving high symmetry in molecular components can pose challenges for creating complex architectures.
• Understanding the role of weak interactions, like C-H···N bonds, is crucial for material stability.

Purpose of the Study:

• To report the construction of an anomalous porous molecular crystal.
• To demonstrate the self-assembly of a complex porous architecture from a single, highly symmetric molecule.
• To investigate the thermal stability and recovery of porosity in the designed crystal.

Main Methods:

• Single-crystal X-ray diffraction to determine the crystal structure and architecture.
• Thermal analysis (e.g., thermogravimetric analysis) to assess thermal stability.
• Gas sorption analysis to confirm porosity and study its recovery.

Main Results:

• An anomalous porous molecular crystal with a segregatively interdigitated architecture was successfully synthesized.
• The crystal is constructed from a single type of fully aromatic multijoint molecule with three dipyridylphenyl wedges.
• The porous structure, stabilized by C-H···N bonds, exhibits porosity up to 202°C and can recover its porosity after thermal treatment upon exposure to acetonitrile vapor.

Conclusions:

• A single, highly symmetric molecule can self-assemble into a complex, porous structure through specific interactions.
• The C-H···N bonds, though labile, provide sufficient stability for the porous framework up to a certain temperature.
• The reversible nature of the porosity highlights a strategy for designing adaptable porous materials.