Frontiers in Single-Crystal Covalent Organic Framework Resolved by Single Crystal X-ray Diffraction

Abstract

The design of covalent organic frameworks (COFs) in single-crystal forms with definite structures that can be resolved by single crystal X-ray diffraction (SCXRD) is a key foundation for their further development. Although significant breakthroughs have been made in the synthesis methods of COFs in recent years, the preparation of COFs with long-range ordered single-crystal structures still faces great challenges. Therefore, this article will systematically summarize the latest research progress in the synthesis strategies of single-crystal COFs that can be resolved by SCXRD. This review aims to summarize the key control parameters in the formation process of single-crystal COFs, comprehensively elaborate on the regulatory laws of different synthesis systems (e.g., solvothermal synthesis, room temperature synthesis, etc.) on the crystal nucleation and growth mechanisms, and focus on exploring the unique advantages of single-crystal structures in precise topological analysis and confirmation relationship research. In addition, we will also discuss the challenges and opportunities of single-crystal COFs in applications like gas adsorption and separation, catalysis, and fuel cells, etc. Overall, this review might provide guidance for the design, structure definition and functional applications of single-crystal COFs.