Columnar self-assembly in electron-deficient heterotriangulenes

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Carbonyl-bridged heterotriangulenes are planar nitrogen-centered polycyclic molecules.
• Soluble derivatives with flexible n-dodecyl chains were synthesized.
• Understanding self-assembly is crucial for designing functional organic materials.

Purpose of the Study:

• To synthesize novel soluble carbonyl-bridged heterotriangulenes.
• To investigate the influence of lateral substituents and spacers on self-assembly.
• To characterize the packing and electronic properties of these compounds.

Main Methods:

• Chemical synthesis of heterotriangulene derivatives.
• X-ray crystallography for single-crystal structure determination.
• Electrochemical studies to assess electronic properties.
• Solution and bulk characterization of self-assembly behavior.

Main Results:

• Successful synthesis of soluble carbonyl-bridged heterotriangulenes with n-dodecyl chains.
• First single-crystal characterization of columnar packing in substituted heterotriangulenes.
• Electrochemical studies revealed a strong acceptor core capable of reversible two-electron transfer.
• Self-assembly behavior was found to be highly dependent on substituent type, steric bulk, and processing conditions.

Conclusions:

• Extending the π-conjugated system with phenylene moieties enhances self-assembly.
• Ethynylene spacers increase flexibility, reducing aggregation tendency.
• Combining phenylene and ethynylene moieties induces thermotropic liquid crystallinity.