Three-Dimensional Mesoporous Covalent Organic Frameworks through Steric Hindrance Engineering
Yujie Wang, Yaozu Liu, Hui Li, Xinyu Guan, Ming Xue, Yushan Yan, Valentin Valtchev, Shilun Qiu, Qianrong Fang
Abstract
The development of three-dimensional (3D) covalent organic frameworks (COFs) with large pores and high surface areas is of great importance for various applications. However, it remains a major challenge due to the frequent structural interpenetration and pore collapse after the removal of guest species situated in the pores. Herein, we report for the first time a series of 3D mesoporous COFs through a general method of steric hindrance engineering. By placing methoxy and methyl groups strategically on the monomers, we can obtain non-interpenetrated 3D COFs of diamondoid structures with permanent mesopores (up to 26.5 Å) and high surface areas (>3000 m 2 g –1 ), which are far superior to those of reported conventional COFs with the same topology. This work thus opens a new avenue to create 3D large-pore COFs for potential applications in adsorption and separation of large inorganic, organic, and biological molecules.