Structural Transformation of Tetracarboxylic Acids Self-Assembly Structures Regulated by a Pyridine Derivative

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Surface Science

Background:

• Understanding molecular self-assembly is crucial for designing novel nanomaterials.
• Hydrogen bonding plays a key role in directing the formation of ordered structures.

Purpose of the Study:

• To investigate the self-assembly of tetracarboxylic acid derivatives (EBTD, BCPTD, DETD).
• To study their co-assembly with pyridine derivative PEBP-C8.
• To elucidate the role of hydrogen bonding in dictating nanostructure formation.

Main Methods:

• Scanning Tunneling Microscopy (STM) for visualizing self-assembled structures.
• Density Functional Theory (DFT) for understanding molecular interactions and bonding.

Main Results:

• EBTD and BCPTD formed regular grid structures via O-H···O hydrogen bonds.
• DETD, with its meta-dicarboxylic group, formed diverse nanostructures, including dimeric building blocks.
• Co-assembly with PEBP-C8 altered hydrogen bonding: EBTD/BCPTD formed acid-pyridine-acid-pyridine structures, while DETD formed both acid-pyridine-acid-pyridine and pyridine-acid-acid-pyridine structures.

Conclusions:

• Molecular structure, specifically the position of carboxylic groups, significantly influences self- and co-assembly behavior.
• Hydrogen bonding (O-H···O vs. O-H···N) dictates the resulting nanostructure and molecular arrangement.
• The findings provide insights into controlling supramolecular architectures for potential applications.