Abstract:

Three new olefin-linked covalent organic frameworks were successfully constructed via Aldol condensation by using 2,4,6-trimethyl-1,3,5-triazine (TMT) with C₃-symmetry and aromatic aldehydes as building units. Under hydrothermal conditions, TMT-TFPT-COF [with 2,4,6-tris(4-formylphenyl)-1,3,5-triazine (TFPT)] and TMT-TFB-COF [with benzene-1,3,5-tricarboxaldehyde (TFB)] were successfully synthesized using NaOH as catalyst, while TMT-TFBA-COF [with 2,3,5,6-tetrafluorobenzene-1,4-dicarbaldehyde (TFBA)] was constructed via trifluoroacetic acid (TFA) catalyst. The COFs structures and olefin-linkages were illustrated by theoretical modeling, FTIR and other characterization methods. The results indicated that all these COFs were constructed via two-dimensional eclipsed structure, and the fluorescent COFs (TMT-TFPT-COF and TMT-TFB-COF) would show great potential applications in the photocatalysis and chemical sensors.

Key words: covalent organic frameworks (COFs), porous organic materials, olefin linkage, Aldol condensation

摘要：

具有C₃对称性的三甲基三嗪（TMT）分别与2,4,6-三(4-醛基苯基)-1,3,5-三嗪（TFPT）、均三苯甲醛（TFB）和四氟对苯二甲醛（TFBA）在酸或者碱催化条件下发生Aldol缩合反应，成功构建出3种新型的碳碳双键桥联的共价有机框架材料（TMT-TFPT-COF、TMT-TFB-COF、TMT-TFBA-COF）。本研究通过Material Studio、ZEO⁺⁺等软件对材料进行结构的精确解析，并结合粉末X射线衍射（PXRD）、傅里叶红外光谱（FTIR）等表征手段确定了材料的结构、连接方式及其荧光特性。结果表明，这3种较高结晶度的新型共价有机框架材料均为二维层层堆积结构，其中碱催化条件下合成的TMT-TFPT-COF、TMT-TFB-COF材料呈现出良好的荧光性质，此类荧光COFs材料在光催化、化学传感器等方面具有很好的应用潜力。

关键词: 共价有机框架材料, 多孔有机材料, 碳碳双键, Aldol反应