Structural Differentiation of Homologous Anisodimensional Frameworks Driven by Site-Selective Polymerization

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Reticular chemistry typically distinguishes structures by dimensional isomers.
• Achieving dimensional differentiation with identical building blocks is challenging due to spatial confinement.
• Site-selective polymerization offers a potential route for creating diverse structures from uniform precursors.

Purpose of the Study:

• To report the dimensional differentiation of covalent organic frameworks (COFs) using site-selective polymerization of identical building blocks.
• To elucidate the mechanism behind this dimensional differentiation.
• To demonstrate the generality of the synthetic strategy and its application in enhancing photocatalysis.

Main Methods:

• Utilizing identical molecular building blocks with a high density of reactive sites.
• Employing aniline to enhance reaction reversibility and modulate monomer conformational flexibility.
• Systematic elucidation of the polymerization mechanism and framework characterization.

Main Results:

• Achieved dimensional differentiation of COFs from identical building blocks for the first time.
• Identified aniline's crucial role in facilitating site-selective polymerization and dimensional control.
• Demonstrated enhanced photocatalytic performance due to residual benzaldehyde acting as exciton acceptors.

Conclusions:

• A novel strategy for regulating COF dimensionality via site-selective polymerization was developed.
• The findings provide insights into controlling building block conformational flexibility for topological transformations.
• This approach offers a new pathway for designing advanced functional materials.