Insight into the Transimination Process in the Fabrication of Surface Schiff-Based Covalent Organic Frameworks
Insight into the Transimination Process in the Fabrication of Surface Schiff-Based Covalent Organic Frameworks
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深入了解表面希夫基共价有机框架制造中的转位过程
DOI：
10.1021/acs.langmuir.9b00565
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发表时间：
2019
期刊：
影响因子：
3.9
通讯作者：
Wang Dong
中科院分区：
文献类型：
--
作者：
Wang Li Mei;Yue Jie Yu;Cao Xiaoyu;Wang Dong
通过在高度取向的热解石墨表面上使用带有醛基的三重对称单体和二位二胺结构单元，研究了单层共价有机框架（sCOF）的表面合成。在反应基团的化学计量比下持续观察到分子1的自组装。然而，只有在二胺单体过量时才能观察到 sCOF 网络的增长。通过研究sCOF网络的生长过程，可以从两个方面来理解过量二胺单体的作用。增加二胺单体的摩尔比为从单体自组装到sCOF网络形成的结构转变提供了驱动力。另一方面，过量的二胺单体为转亚胺反应提供了基础环境，促进了高度有序的sCOF的形成。目前的工作提供了对亚胺基 COF 合成中转亚胺化反应作用的分子理解。
The on-surface synthesis of single-layered covalent organic frameworks (sCOFs) has been investigated by employing a 3-fold symmetric monomer1carrying aldehyde groups and the ditopic diamine building block2on a highly oriented pyrolytic graphite surface. The self-assembly of molecule1is persistently observed at the stoichiometric ratio of the reactive groups. The growth of sCOF network is observed, however, only at the excess of diamine monomers. By investigating the growth process of the sCOF network, the role of excessive diamine monomers can be understood by two aspects. Increasing the molar ratio of diamine monomer provides the driving force for the structural transition from the monomer self-assembly to the formation of the sCOF network. On the other hand, the excess diamine monomers provide basic environment for the transimination reaction and promote the formation of highly ordered sCOFs. The present work provides molecular understanding of the role of transimination reaction in imine-based COF synthesis.