Deng Wen-Chao, Qian Hai-Long, Yang Cheng, Xu Shu-Ting, Yan Xiu-Ping
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China; Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
Institute of Analytical Food Safety, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
Talanta. 2025 Jan 1;282:127012. doi: 10.1016/j.talanta.2024.127012. Epub 2024 Oct 9.
Covalent organic frameworks (COFs) has shown great potential as stationary phase in gas chromatography separation. However, designing COF stationary phases with high separation performance remains challenging. Here, we report a novel strategy to enhance the separation ability of COF stationary phases through tuning the interlayer stacking of COF. A rare interlayer modulation of 2D COFs from eclipsed-AA to slipped-AA was achieved through a two-step synthesis method. Simply changing the solvent used in step 1 allowed an interlayer modulation from slipped-AA to eclipsed-AA. As the proof-of-concept, 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphyrin (Tph) and 2,5-dihydroxyterephthalaldehyde (DHTA) were condensed to prepare 2D COF Tph-DHTA. The interlayer stacking of the 2D COF Tph-DHTA was tuned from eclipsed-AA model to slipped-AA by changing the solvent from o-dichlorobenzene + n-butanol (3:1, v/v) to tetrahydrofuran + n-butanol (1:7, v/v) in step 1. The as-prepared Tph-DHTA with slipped-AA stacking (s-Tph-DHTA) showed higher resolution and faster separation of C8 aromatic isomers than that with eclipsed-AA stacking (e-Tph-DHTA). The formation of slipping stacking of s-Tph-DHTA facilitated the thermodynamics, but did not affect the mass transfer resistance for the separation of C8 aromatic isomers. This work not only provides a promising way to modulate the stacking structure of COFs, but also opens a new strategy to design COF stationary phases for the separation of intractable isomers.
共价有机框架（COFs）在气相色谱分离中作为固定相已显示出巨大潜力。然而，设计具有高分离性能的COF固定相仍然具有挑战性。在此，我们报告了一种通过调节COF的层间堆积来增强COF固定相分离能力的新策略。通过两步合成法实现了二维COFs从重叠-AA到错位-AA的罕见层间调制。仅改变第一步中使用的溶剂就可以实现从错位-AA到重叠-AA的层间调制。作为概念验证，将5,10,15,20-四（4-氨基苯基）-21H,23H-卟啉（Tph）和2,5-二羟基对苯二甲醛（DHTA）缩合制备二维COF Tph-DHTA。通过在第一步中将溶剂从邻二氯苯+正丁醇（3:1，v/v）改为四氢呋喃+正丁醇（1:7，v/v），将二维COF Tph-DHTA的层间堆积从重叠-AA模型调整为错位-AA。所制备的具有错位-AA堆积的Tph-DHTA（s-Tph-DHTA）比具有重叠-AA堆积的（e-Tph-DHTA）对C8芳烃异构体显示出更高的分辨率和更快的分离速度。s-Tph-DHTA错位堆积的形成促进了热力学，但不影响C8芳烃异构体分离的传质阻力。这项工作不仅提供了一种调节COFs堆积结构的有前景的方法，而且为设计用于分离难处理异构体的COF固定相开辟了新策略。
