Restricted Growth of Vinylene-Linked Covalent Organic Frameworks along Two-Dimensional Plane Using Heterogeneous...

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Vinylene-linked covalent organic frameworks (viCOFs) are typically synthesized using homogeneous catalysts.
• Homogeneous catalysis often leads to uncontrolled layer growth, hindering the formation of highly ordered viCOFs.
• Existing methods face challenges in achieving high crystallinity and scalability.

Purpose of the Study:

• To develop a scalable protocol for synthesizing highly ordered 2D viCOFs.
• To investigate the use of heterogeneous catalysts for improved viCOF synthesis.
• To elucidate the growth mechanism of viCOFs under heterogeneous catalysis.

Main Methods:

• Introduction of polyoxometalates (POMs) as heterogeneous catalysts.
• Utilizing POMs' Brønsted alkalinity and catalytic surface to direct 2D layer growth.
• Employing density functional theory (DFT) calculations and experimental validation.

Main Results:

• Successful synthesis of six typical 2D viCOFs with high crystallinity and porosity.
• Demonstrated restriction of out-of-plane branching, leading to enhanced 2D structure.
• Revealed a bottom intercalation growth pattern, promoting ordered monomer assembly.
• Achieved shorter reaction times compared to homogeneous catalysis methods.
• Gram-scale preparation of 2D viCOFs was demonstrated.

Conclusions:

• Heterogeneous catalysis using POMs offers a novel and effective strategy for synthesizing high-quality 2D viCOFs.
• The developed method provides a scalable and efficient route to crystalline viCOFs.
• This approach offers new insights into the synthetic methodologies for covalent organic frameworks (COFs).