Efficient Adsorption of Acetylene over CO 2 in Bioinspired Covalent Organic Frameworks.

Rational design of covalent organic frameworks (COFs) to broaden their diversity is highly desirable but challenging due to the limited, expensive, and complex building blocks, especially compared with other easily available porous materials. In this work, we fabricated two novel bioinspired COFs, namely, NUS-71 and NUS-72, using reticular chemistry with ellagic acid and triboronic acid-based building blocks. Both COFs with AB stacking mode exhibit high acetylene (C 2 H 2 ) adsorption capacity and excellent separation performance for C 2 H 2 /CO 2 mixtures, which is significant but rarely explored using COFs. The impressive affinities for C 2 H 2 appear to be related to the sandwich structure formed by C 2 H 2 and the host framework via multiple host-guest interactions. This work not only represents a new avenue for the construction of low-cost COFs but also expands the variety of the COF family using natural biochemicals as building blocks for broad application.