Isoreticular covalent organic frameworks for hydrocarbon uptake and separation: the important role of monomer planarity

Covalent organic frameworks (COFs) represent a new class of crystalline porous organic materials with huge potential in gas storage and separation. Here we present three isoreticular COFs sharing identical two-dimensional layered structures but with different planarity of the building monomers, leading to various crystallinities, porosities and hydrocarbon uptake and separation performances. This study reveals the importance of monomer design in the long-range stacking of COFs, which can be used to tailor COFs with target functionalities for specific applications.