Hierarchical Microtubular Covalent Organic Frameworks Achieved by COF‐to‐COF Transformation. (17th March 2023)

• Record Type: Journal Article
• Authors: Mu, Zhenjie; Zhu, Yuhao; Zhang, Yufeng; Dong, Anwang; Xing, Chunyan; Niu, Ziru; Wang, Bo; Feng, Xiao
• Is Part Of: Angewandte Chemie. Volume 135:Number 17(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-17
• Subjects: COF-to-COF Transformation -- Covalent Organic Frameworks -- Crystalline Porous Materials -- Hierarchical COFs; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202300373
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Pore environment and aggregated structure play a vital role in determining the properties of porous materials, especially regarding the mass transfer. Reticular chemistry imparts covalent organic frameworks (COFs) with well‐aligned micro/mesopores, yet constructing hierarchical architectures remains a great challenge. Herein, we reported a COF‐to‐COF transformation methodology to prepare microtubular COFs. In this process, the C 3 ‐symmetric guanidine units decomposed into C 2 ‐symmetric hydrazine units, leading to the crystal transformation of COFs. Moreover, the aggregated structure and conversion degree varied with the reaction time, where the hollow tubular aggregates composed of mixed COF crystals could be obtained. Such hierarchical architecture leads to enhanced mass transfer properties, as proved by the adsorption measurement and chemical catalytic reactions. This self‐template strategy was successfully applied to another four COFs with different building units. Abstract : Hierarchically microtubular covalent organic frameworks (COFs) were achieved by a COF‐to‐COF transformation process, where the C 3 ‐symmetric guanidine units were decomposed into C 2 ‐symmetric hydrazine units. The mixed COFs with hierarchical architectures exhibited much‐improved efficiency and selectivity in catalyzing CO2 reduction with phenylsilane and N ‐methylaniline due to enhanced mass transport ability.