Synthesis of C-C Bonded Two-Dimensional Conjugated Covalent Organic Framework Films by Suzuki Polymerization on a Liquid-Liquid Interface.

Synthesis of free-standing two-dimensional (2D) conjugated covalent organic framework (COF) films linked by C-C bonds is highly desirable. Now a very simple and mild strategy has been developed to synthesize them by Suzuki polymerization on a water-toluene interface in a refrigerator. The versatility of this strategy was confirmed by the successful synthesis of two different 2D-COF films: a porous graphene and a porphyrin-contained 2D-COF. Both 2D-COF films have large lateral size and their crystalline domains were visualized by high resolution TEM. Based on the wide compatibility of Suzuki reaction, our breakthrough work opened a door for the synthesis of various 2D conjugated COF films. For application studies, the porous graphene exhibits a good carrier mobility, which is much higher than -C=N- linked 2D COF films and a good catalytic activity for hydrogen evolution reaction, which is comparable with nitrogen- or phosphorus-doped graphene.