Truncating 2D Framework Materials Down to a Single Pore: Synthetic Approaches and Opportunities

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Conjugated two-dimensional (2D) framework materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), are vital for coupling semiconductivity and porosity.
• However, inherent limitations like strong π-π stacking hinder processability and active site accessibility in traditional 2D architectures.

Purpose of the Study:

• To explore the synthesis and advantages of truncating 2D conjugated frameworks into single macrocycles.
• To demonstrate how these macrocycles can overcome the limitations of their 2D counterparts.

Main Methods:

• Synthesized conjugated macrocycles using ditopic analogues of common tritopic ligands for 2D MOFs and COFs.
• Varied peripheral side chain length, aromatic core size, and intermediate solubility to control macrocycle formation.
• Investigated the impact of peripheral side chains on solubility, stability, and morphology.

Main Results:

• Developed a diverse library of conjugated macrocycles mimicking the form and function of 2D frameworks.
• Achieved improved processability, surface tunability, and mass transport properties compared to 2D materials.
• Demonstrated enhanced electronic device fabrication and electrochemical performance due to solution processability and nanoscale dimensions.

Conclusions:

• Simple macrocycles preserve essential properties like porosity and conductivity from 2D frameworks.
• Macrocycles offer superior processability, precise surface tuning, and better active site accessibility.
• These macrocycles serve as a crucial link between molecular and extended framework systems, opening new avenues for applications.