Efficient Photocatalytic Oxidation of Aromatic Alcohols over Thiophene-based Covalent Triazine Frameworks with A Narrow Band Gap

Photocatalytic selective oxidation of aromatic alcohols by covalent organic frameworks (COFs) is a sustainable strategy to replace present metal-based heterogeneous catalytic oxidation systems. Covalent triazine-based frameworks (CTFs), a subgroup of COFs, possess promising properties as efficient catalysts for photocatalytic oxidation. Sulfur-containing metal-free CTFs exhibit a good performance in photocatalysis due to their narrowed band gap, and the fast generated photoelectrons/holes separation and transfer. Here, we report the synthesis of thiophene-based CTFs under mild conditions for photocatalytic oxidation of aromatic alcohols to the corresponding benzaldehydes using pure oxygen as the oxidant. Full conversion and a selectivity as high as 90 % to benzaldehyde were obtained paving the way for a potential application of these metal-free photocatalysts in fine chemicals synthesis.