Switching porosity of stable triptycene-based cage via solution-state assembly processes

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Tuning the porosity of porous materials presents a significant challenge.
• The solubility of most porous organic cages offers potential for solution-based porosity regulation.

Purpose of the Study:

• To demonstrate that triptycene-based cages (TCs) exhibit tunable porosity through solution-state assembly.
• To investigate the stability and porosity characteristics of TCs under various conditions.

Main Methods:

• Synthesized triptycene-based cages (TCs).
• Investigated TC stability in acidic, basic, and boiling water conditions.
• Controlled porosity by varying solution-state assembly processes, specifically slow crystallization versus rapid precipitation from methanol/dichloromethane.

Main Results:

• TCs demonstrated stability in acid, base, and boiling water.
• Slow crystallization of TC molecules from solution resulted in nearly non-porous materials (off-state).
• Rapid precipitation yielded porous TC materials (TC-rp) with a high BET surface area of 653 m² g⁻¹ (on-state).

Conclusions:

• The porosity of triptycene-based cages can be effectively tuned by controlling solution assembly methods.
• Solution processability provides a viable strategy for designing porous materials with switchable porosity.