State Key Laboratory 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.
ACS Appl Mater Interfaces. 2017 Jul 26;9(29):24999-25005. doi: 10.1021/acsami.7b08060. Epub 2017 Jul 13.
High crystallinity of covalent organic frameworks (COFs) with dual fluorescence emissions has not been reported so far. Here, we show the rational design and preparation of high-crystallinity COF TzDa via the synergetic interaction of docking sites and hydrogen bonds: 4,4',4″-(1,3,5-Triazine-2,4,6-triyl)trianiline (Tz) with the docking site and 2,5-dihydroxyterephthalaldehyde (Da) with the OH group are employed to synthesize the imine-linked two-dimensional high-crystallinity layered structure TzDa. The prepared mesoporous TzDa (ca. 36 Å) exhibits high thermal and chemical stability. The intramolecular charge transfer (ICT) and excited-state intramolecular proton transfer (ESIPT) effects bring TzDa two main fluorescence emissions around 500 and 590 nm. Water molecules can interfere with the ICT and ESIPT effects, allowing the development of a ratiometric fluorescent sensor for water in organic solvents. The proposed sensor shows high sensitivity to trace water in conventional organic solvents. The high stability of TzDa allows its recyclable uses for trace water detection. This work not only offers a platform for the construction of high-crystallinity COFs, but also provides a rational design of COFs with dual fluorescence emissions for ratiometric sensing applications.
到目前为止，还没有报道具有双荧光发射的共价有机骨架（COFs）具有高结晶度。在这里，我们通过对接位点和氢键的协同作用展示了高结晶 COF TzDa 的合理设计和制备：带有对接位点的 4,4',4″-(1,3,5-三嗪-2,4,6-三基)三苯胺（Tz）和带有 OH 基团的 2,5-二羟基对苯二甲醛（Da）被用于合成亚胺连接的二维高结晶层状结构 TzDa。所制备的介孔 TzDa（约 36 Å）表现出高热和化学稳定性。分子内电荷转移（ICT）和激发态分子内质子转移（ESIPT）效应使 TzDa 在 500nm 和 590nm 左右产生两个主要的荧光发射。水分子可以干扰 ICT 和 ESIPT 效应，从而开发出用于有机溶剂中水分的比率荧光传感器。所提出的传感器对常规有机溶剂中的痕量水具有高灵敏度。TzDa 的高稳定性允许其可重复用于痕量水检测。这项工作不仅为构建高结晶 COFs 提供了一个平台，而且为具有双荧光发射的 COFs 提供了用于比率传感应用的合理设计。
