Crystal Structures of a Molecule Designed Not To Pack Tightly

Area of Science:

• Materials Science
• Crystallography
• Organic Chemistry

Background:

• Organic molecules of intrinsic microporosity (OMIMs) exhibit loose structural packing due to weak intermolecular forces.
• This inherent characteristic leads to OMIMs predominantly existing and being studied in amorphous states.
• Crystallization of OMIMs for detailed structural analysis, such as X-ray diffraction, is typically challenging.

Purpose of the Study:

• To investigate the crystalline nature of a specific OMIM previously only characterized as amorphous.
• To explore and describe the potential for polymorphism in OMIMs.
• To overcome the difficulties in obtaining single crystals of OMIMs for structural elucidation.

Main Methods:

• Synthesis and isolation of an OMIM.
• Crystallization experiments to induce solid-state structural formation.
• X-ray diffraction analysis to characterize the obtained crystalline structures.

Main Results:

• Successfully obtained and identified four distinct crystalline polymorphs of the target OMIM.
• Characterized the unique crystal structures of each polymorph.
• Demonstrated that OMIMs, despite their amorphous nature, can exhibit polymorphism.

Conclusions:

• The study successfully challenges the notion that OMIMs are exclusively amorphous.
• The discovery of multiple polymorphs provides new avenues for understanding and utilizing OMIMs.
• This work opens possibilities for crystal engineering and structure-property relationship studies in OMIMs.