Two-dimensional bricklayer arrangements of tolans using halogen bonding interactions

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Electronics

Background:

• Diphenylacetylene (tolan) derivatives are key building blocks in organic electronics.
• Controlling molecular packing is crucial for tuning the properties of organic semiconductors.
• Halogen bonding is an important non-covalent interaction for directing self-assembly.

Purpose of the Study:

• To investigate the role of halogen bonding in directing the solid-state packing of diphenylacetylene derivatives.
• To explore the formation of 2D bricklayer motifs using halogen bonding interactions.
• To assess the potential of this strategy for designing organic semiconductors with specific packing arrangements.

Main Methods:

• Synthesis of diphenylacetylene derivatives bearing self-complementary aryl halides and halogen bond-accepting nitriles.
• Single-crystal X-ray diffraction analysis to determine molecular packing motifs.
• Comparative studies with fluorinated analogues lacking strong halogen bonding capabilities.

Main Results:

• Diphenylacetylene derivatives with effective halogen bond donors and acceptors formed 2D bricklayer packing motifs.
• The presence of strong halogen bonding interactions was directly correlated with the formation of the desired bricklayer structure.
• Absence of halogen bonding, as seen with fluorinated aryl bromides, led to alternative, less ordered packing motifs.
• The 2D bricklayer motif is a rarely observed packing arrangement in organic materials.

Conclusions:

• Halogen bonding is a powerful tool for controlling the supramolecular assembly of diphenylacetylene derivatives.
• The formation of 2D bricklayer packing can be reliably achieved through strategic design utilizing halogen bonding.
• This approach offers a promising route for the rational design of organic semiconductors with tailored solid-state structures.