Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies
Zixing Zhang, Shuai Bi, Fancheng Meng, Xiaomeng Li, Mengqi Li, Kaiwen Mou, Dongqing Wu, Fan Zhang
Abstract
A D 3 h -symmetric hexatopic monomer was first prepared by attaching the three-fold ditopic moiety 2,6-dimethylpyridine to the meta -positions of a phenyl ring. It was further condensed at its six pyridylmethyl carbons with linear ditopic aromatic dialdehydes, resulting in two vinylene-linked COFs with heteroporous topologies, as revealed by powder X-ray diffraction (PXRD), nitrogen sorption, and pore-size distribution analyses, as well as transmission electron microscopy (TEM) image. The linear- and cross-conjugations, respectively, arising from the 2,6-linked pyridines and meta -linked phenylenes in the hexatopic nodes rendered the resultant COFs with well-patterned π-delocalization, allowing for efficiently catalyzing the bromination of aromatic derivatives with the pore-size-dependent conversion yields and regioselectivity under the irradiation of green light.