Three-Dimensional Covalent Organic Frameworks with hea Topology

Abstract

Three-dimensional (3D) covalent organic frameworks (COFs) are a new type of crystalline organic porous material, which have great application potential in various fields due to their complex pore structures and fully exposed active sites. The synthesis of 3D COFs with novel topologies is still challenging on account of limited secondary building units. Herein, we report a 3D COF with hea topology, which has never been reported before, utilizing a D3h-symmetric precursor [2,3,6,7,14,15-hexakis(4-formylphenyl)triptycene (HFPTP)] and [tetrakis(4-amino biphenyl)methane (TABPM)]. 3D-hea-COFs display permanent porosity and a Brunauer–Emmett–Teller surface area of 1804.0 m2 g–1. Owing to the huge internal free volume of triptycene, 3D-hea-COFs show good adsorption performance for H2, CO2, and CH4. Moreover, theoretical calculation reveals that both triptycene and tetraphenylmethane units contribute to enhance hydrogen storage capacity. The novel topology in this work expands the family of 3D COFs and provides new possibilities for designing efficient gas storage materials.