Li Liuxiao, Yun Qinbai, Zhu Chongzhi, Sheng Guan, Guo Jun, Chen Bo, Zhao Meiting, Zhang Zhicheng, Lai Zhuangchai, Zhang Xiao, Peng Yongwu, Zhu Yihan, Zhang Hua
Department of Chemistry, City University of Hong Kong, Hong Kong, China.
Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
J Am Chem Soc. 2022 Apr 13;144(14):6475-6482. doi: 10.1021/jacs.2c01199. Epub 2022 Apr 4.
Two-dimensional (2D) covalent organic frameworks (COFs) possess designable pore architectures but limited framework topologies. Until now, 2D COFs adopting the topology with ordered and rhombic pore geometry have rarely been reported. Here, an isoreticular series of 2D COFs with the topology and controllable pore size is synthesized by employing a -symmetric aldehyde, ., hexa(4-formylphenyl)benzene (HFPB), and -symmetric amines ., tris(4-aminophenyl)amine (TAPA), tris(4-aminophenyl)trazine (TAPT), and 1,3,5-tris[4-amino(1,1-biphenyl-4-yl)]benzene (TABPB), as building units, referred to as HFPB-TAPA, HFPB-TAPT, and HFPB-TABPB, respectively. The micropore dimension down to 6.7 Å is achieved in HFPB-TAPA, which is among the smallest pore size of reported 2D COFs. Impressively, both the in-plane network and stacking sequence of the 2D COFs can be clearly observed by low-dose electron microscopy. Integrating the unique topology with small rhombic micropores, these 2D COFs are endowed with both short molecular diffusion length and favorable host-guest interaction, exhibiting potential for drug delivery with high loading and good release control of ibuprofen.
二维（2D）共价有机框架（COF）具有可设计的孔结构，但框架拓扑结构有限。到目前为止，很少有报道采用具有有序菱形孔几何结构拓扑的二维COF。在此，通过使用一种对称醛，即六（4-甲酰基苯基）苯（HFPB），和对称胺，即三（4-氨基苯基）胺（TAPA）、三（4-氨基苯基）三嗪（TAPT）和1,3,5-三[4-氨基（1,1-联苯-4-基）]苯（TABPB）作为构建单元，合成了一系列具有该拓扑结构且孔径可控的等规二维COF，分别称为HFPB-TAPA、HFPB-TAPT和HFPB-TABPB。在HFPB-TAPA中实现了低至6.7 Å的微孔尺寸，这是已报道的二维COF中最小的孔径之一。令人印象深刻的是，通过低剂量电子显微镜可以清晰地观察到二维COF的面内网络和堆积序列。将独特的拓扑结构与小菱形微孔相结合，这些二维COF具有短分子扩散长度和良好的主客体相互作用，在布洛芬的高负载和良好释放控制的药物递送方面展现出潜力。
