Two-dimensional crystalline covalent triazine frameworks via dual modulator control for efficient photocatalytic oxidation of sulfides

Two-dimensional crystalline covalent triazine frameworks (2D-CTFs) are emerging 2D materials with the characteristics of fully annulated conjugated structures and aromatic nitrogen-rich skeletons. Due to the difficulty in the control of the polymerization dynamics, the preparation of crystalline 2D-CTFs is still a daunting challenge compared to that of other organic framework materials. Herein, we report the construction of crystalline 2D-CTFs using dual modulator control, in which aniline and a co-solvent are used as dual modulators for a dynamic covalent linkage formation and non-covalent self-assembly process, respectively. The strategy successfully leads to crystalline CTFs from different functional building blocks. The crystalline CTFs could be further regulated via peripheral functionalization, which dramatically boosted the photocatalytic activity for oxidation of sulfides into sulfoxides, and excellent conversion rates and selectivity for a wide range of sulfides with various functional groups were achieved after functionalization with methoxyl groups. This work gives new insights into the design and synthesis of crystalline CTFs for photocatalytic applications.