Polymorphs of layered assemblies of hydrogen-bonded hexagonal networks caused by conformational frustration

Abstract

Generation of four polymorphs of 2D-nCOF crystals that are formed through stacking of a hydrogen-bonded, hexagonally-networked framework is revealed for the first time. The structural diversity is caused not from the topology or the stacking manner of the framework but from subtle structural factors such as rotational conformation and location of conformational frustration within the framework.