Imidazole-Dependent Assembly of Copper Polymolybdate Frameworks for One-Pot Sulfide Oxidation and C–H Activation

With the arising concern of environmental problems, the removal of polycyclic aromatic hydrocarbons or sulfides in fuel oils is an indispensable process to achieve a clean energy source. At present, direct catalytic oxidation of benzyl C–H bonds of polycyclic aromatic hydrocarbons and sulfides to corresponding carbonyl compounds is very attractive, yet their simultaneous oxidation using a single economical-friendly catalyst is not yet well established. Here, three imidazole-decorated copper polyoxomolybdate frameworks (Im-Cu-PMoFs) are successfully synthesized by tuning different imidazole derivatives. These Im-Cu-PMoFs can serve as effective heterogeneous catalysts for the one-pot oxidation of benzylic hydrocarbons and sulfides to produce carbonyl compounds. Specifically, Im-Cu-PMoFs-3 as a single component catalyst exhibits high activity and prominent selectivity (conversion up to 99% and selectivity up to 99%) in the one-pot reaction. In addition, the possible reaction pathway and active sites are supported by sufficient characterizations and DFT calculations, which reveal the synergistic effect of Mo­(VI) and Cu­(II) centers in the one-pot catalysis reaction. These dual function-validated frameworks hold much promise in the exploration of novel catalysts for applications like continuous catalytic or flow bed reaction.