Increasing connectivity through self-complementarity enables permanent porosity in a halogen-bonded organic framework

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Crystallography

Background:

• Halogen bonding is a key interaction for creating ordered molecular solids.
• Achieving permanent porosity in halogen-bonded materials has been a significant challenge.

Purpose of the Study:

• To report the first rigorously characterized permanently porous halogen-bonded organic framework (XOF).
• To demonstrate a self-complementary strategy for creating stable, porous XOFs.

Main Methods:

• Synthesis of a 2-iodooxazole-terminated tecton.
• Spontaneous assembly into a crystalline network.
• Characterization using N2 gas adsorption-desorption at 77 K and X-ray diffraction.

Main Results:

• The first permanently porous halogen-bonded organic framework (XOF) was successfully synthesized.
• The XOF exhibited a stable, low-density crystalline network intact after solvent removal.
• The framework demonstrated 3D connectivity via C-I⋯N halogen bonding and π-stacking.

Conclusions:

• Halogen bonding can support permanent porosity, overcoming previous limitations.
• XOFs represent a new class of permanently porous materials with robust intermolecular interactions.
• This work expands the potential of halogen bonding in advanced materials design.