A Wavy Two-Dimensional Covalent Organic Framework from Core-Twisted Polycyclic Aromatic Hydrocarbons

A high degree of
crystallinity is an essential aspect in two-dimensional
covalent organic frameworks, as many properties depend strongly on
the structural arrangement of the different layers and their constituents.
We introduce herein a new design strategy based on core-twisted polycyclic
aromatic hydrocarbon as rigid nodes that give rise to a two-dimensional
covalent organic framework with a wavy honeycomb (chairlike) lattice.
The concave–convex self-complementarity of the wavy two-dimensional
lattice guides the stacking of framework layers into a highly stable
and ordered covalent organic framework that allows a full 3D analysis
by transmission electron microscopy revealing its chairlike honeycomb
facets and aligned mesoporous channels. Remarkably, the waviness of
the framework does not disrupt the interlayer π–π
stacking that shows charge transporting properties similar to those
of planar covalent organic frameworks. The implementation of core-twisted
aromatics as building blocks for covalent organic frameworks brings
new possibilities in the design of highly ordered organic materials.