2D covalent organic frameworks for photosynthesis of α-trifluoromethylated ketones from aromatic alkenes

Photoactive two-dimensional covalent organic frameworks (2D-COFs) have recently emerged as a promising platform for efficient solar to chemical energy conversion. The photosynthesis of α-trifluoromethylated ketones, which is an important access to various fluorine-containing compounds, is rarely reported in heterogeneous photocatalytic systems. Herein, we report two 2D-COFs constructed from the electron-deficient triazine and electron-rich benzotrithiophene units with imine and amide linkages for the photosynthesis of α-trifluoromethylated ketones. The novel triazine-based COFs showed good activity, broad substrate flexibility and recyclability under visible-light irradiation, which is much superior to the classical pyrene-based COFs. Density functional theory calculations revealed that the triazine-based COFs have intrinsically lower carrier recombination tendency and can produce more intermediates •CF3, resulting in higher catalytic efficiency. This research will contribute to the rational design of photoactive COFs and facilitate the development of fluorine chemistry.