Covalent organic frameworks as metal-free heterogeneous photocatalysts for organic transformations

Two-dimensional covalent organic frameworks (2D-COFs) are excellent candidates for photocatalytic organic transformations due to their periodic columnar π-arrays and ordered nanochannels. Here, we present a novel 2D-COF that features permanent porosity with high surface area and large pore volume, and exhibits a high crystallinity and an excellent stability. Indeed, the new 2D-COF was found to be a highly efficient, metal-free, recyclable heterogeneous photocatalyst for oxidative C-H functionalizations under visible-light irradiation using O₂ as a green oxygen source.