Self-assembling molecular trees containing octa-p-phenylene: from nanocrystals to nanocapsules

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Nanotechnology

Background:

• Dendrimers and dendritic molecules offer unique structural properties for self-assembly.
• Controlling molecular architecture is key to designing novel nanomaterials.

Purpose of the Study:

• To synthesize and characterize tree-shaped molecules with varying flexible headgroups.
• To investigate the self-assembly behavior of these molecules in solution.
• To explore the formation of different nanostructures and their properties.

Main Methods:

• Synthesis of octa-p-phenylene based tree-shaped molecules.
• X-ray scattering and transmission electron microscopy (TEM) for structural analysis.
• Optical spectroscopy to study electronic properties.
• Dynamic and static light scattering, scanning electron microscopy (SEM) for aggregate characterization.

Main Results:

• Molecules with small flexible heads self-assembled into lamellar structures.
• Molecules with larger heads formed discrete heptameric bundles organizing into 3-D primitive orthorhombic supercrystals.
• In selective solvents, molecules formed capsule-like hollow aggregates.
• Optical properties differed between lamellar and 3-D supercrystalline structures.

Conclusions:

• Tree-shaped molecules can form organized nanocrystals with parallel arrangement.
• Hollow nanocapsules with radial arrangement are also achievable.
• Self-assembly outcome is tunable by molecular design (headgroup size) and solvent environment.