Li Shengxu, Xu Shunqi, Lin En, Wang Tonghai, Yang Haoyong, Han Junyi, Zhao Yuxiang, Xue Qunji, Samorì Paolo, Zhang Zhenjie, Zhang Tao
Key Laboratory of Advanced Marine Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Chem. 2025 Feb;17(2):226-232. doi: 10.1038/s41557-024-01690-y. Epub 2025 Jan 6.
sp-carbon-linked covalent organic frameworks (spc-COFs) are crystalline porous polymers with repeat organic units linked by sp carbons, and have attracted increasing interest due to their robust skeleton and tunable semiconducting properties. Single-crystalline spc-COFs with well-defined structures can represent an ideal platform for investigating fundamental physics properties and device performance. However, the robust olefin bonds inhibit the reversible-reaction-based crystal self-correction, thus yielding polycrystalline or amorphous polymers. Here we report an imine-to-olefin transformation strategy to form single-crystal spc-COFs. The isolated single crystals display rectangular nanotube-like domains with sizes up to approximately 24 μm × 0.8 μm × 0.8 μm, and permanent pore distribution around 1.1 nm. The highly conjugated olefin linkage endows the crystals with enhanced electronic connectivity which determines a remarkable room-temperature metal-free ferromagnetism (8.6 × 10 emu g). Our protocol is robust and generally applicable for the synthesis of single-crystalline spc-COFs for future spin-electron devices.
sp-碳连接的共价有机框架（spc-COFs）是由sp碳连接重复有机单元的结晶多孔聚合物，由于其坚固的骨架和可调节的半导体特性而受到越来越多的关注。具有明确结构的单晶spc-COFs可以作为研究基本物理性质和器件性能的理想平台。然而，坚固的烯烃键抑制了基于可逆反应的晶体自我校正，从而产生多晶或非晶聚合物。在此，我们报告一种亚胺到烯烃的转化策略来形成单晶spc-COFs。分离出的单晶呈现出尺寸达约24μm×0.8μm×0.8μm的矩形纳米管状区域，以及约1.1nm的永久孔隙分布。高度共轭的烯烃键赋予晶体增强的电子连通性，这决定了其显著的室温无金属铁磁性（8.6×10 emu g）。我们的方法很可靠，普遍适用于合成用于未来自旋电子器件的单晶spc-COFs。
