Boronic ester Sierpiński triangle fractals: from precursor design to on-surface synthesis and self-assembling...

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Nanotechnology

Background:

• Fractal structures offer unique properties for advanced materials.
• Covalent organic frameworks (COFs) are a class of porous crystalline materials.
• Developing scalable methods for constructing complex fractal architectures is challenging.

Purpose of the Study:

• To design and synthesize a precursor for constructing covalent Sierpiński triangle (ST) fractals.
• To investigate methods for assembling these ST fractals under ambient conditions.
• To enable the large-scale production of ordered ST superstructures for property studies.

Main Methods:

• Synthesis of a three-fold node precursor molecule.
• Construction of covalent ST fractals via boronic ester linkages.
• Utilizing liquid/solid interface assembly at room temperature.
• Employing thermal annealing in a water atmosphere for superstructure formation.

Main Results:

• Successful synthesis of a precursor suitable for fractal construction.
• Demonstrated formation of covalent ST fractals under two different conditions.
• Achieved large-scale, ordered superstructures of covalent STs through thermal annealing.
• Established a pathway for investigating the properties of these novel fractal materials.

Conclusions:

• Covalent Sierpiński triangle fractals can be efficiently constructed using the designed precursor.
• Thermal annealing provides a scalable route to ordered fractal superstructures.
• This work facilitates future research into the functional properties of covalent fractals.