Electronic Structure of Two-Dimensional π-Conjugated Covalent Organic Frameworks

Increasing attention is being given to the development of covalent organic frameworks (COFs) that are based on monolayers of fully pi-conjugated structures. At first glance, such two-dimensional (2D) polymer networks could simply be viewed as a mere extension into a second dimension of the quasi-one-dimensional (1D) conjugated polymers at the origin of the field of organic electronics. However, such a view misses essential characteristics coming specifically from 2D lattice symmetry. Our aims in this Perspective are twofold. We seek (i) to provide a conceptual, chemistry-oriented theoretical description of the impact on the electronic structure of this extension from 1D to 2D and (ii) to establish chemical structure symmetry electronic property relationships for this class of 2D pi-conjugated COFs.