Two dimensional self-assembly of bis-acylureas having various functional end groups

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Synthesis

Background:

• Bis-acylureas are molecules with repeating acylurea units.
• Self-assembly is crucial for creating ordered structures from molecular building blocks.
• Tailoring functional end groups influences supramolecular assembly.

Purpose of the Study:

• To synthesize and investigate the self-assembly behavior of novel bis-acylurea molecules.
• To explore the impact of various functional end groups on supramolecular structure formation.
• To characterize the resulting supramolecular architectures.

Main Methods:

• Synthesis of bis-acylureas via coupling reactions.
• Spontaneous self-assembly upon cooling from isotropic solutions.
• Characterization using single crystal X-ray diffraction.
• Morphological studies of supramolecular structures.

Main Results:

• Thirteen bis-acylureas with diverse end groups (aliphatic, benzyl, thiophenyl, sulfur-containing, propargyl) were synthesized.
• Molecules with aliphatic, benzyl, and thiophenyl groups formed 2D supramolecular structures with flat surfaces.
• Sulfur-containing derivatives self-organized into 2D superstructures, while thiol derivatives precipitated irregularly.
• Propargyl derivatives formed low-order superstructures, but click reaction derivatives exhibited lamellar packing and nanosheet formation.

Conclusions:

• Bis-acylurea structure and functional end groups dictate self-assembly behavior and resulting supramolecular architectures.
• Ordered 2D structures and crystalline grids are achievable with specific functional groups.
• Click chemistry offers a route to lamellar packing and nanosheet formation in bis-acylurea derivatives.