Molecular Photocatalysts Based on Quinolinium-Grafted Polyoxometalates for Efficient One-Step Aerobic Oxidation of Benzyl Alcohols to Benzoic Acids

Based on the need for green synthesis, photocatalytic oxidation reactions under ambient conditions are vitally significant. Herein, we developed six new quinolinium-grafted polyoxometalate (Q-POM) structures and explored their photocatalytic ability in the photocatalytic aerobic oxidation of benzyl alcohol-like compounds. Among them, (Bu4N)2+{AlMo6O18[(OCH2)3CCH3][(OCH2)3CNHCOCH2C9H7N]}2– (TBA-Q-Al) can achieve the one-step oxidation of various benzyl alcohols to the corresponding benzoic acid compounds with favorable yields under blue light irradiation at 420–430 nm accompanied by oxygen as the sole oxidant. The photocatalyst combines the ability of quinolinium π–π conjugation to respond to light and the property of the POM backbone to storage-transfer electrons. This work provides guidance for the subsequent development of more efficient quinolinium-grafted POM structures for photocatalytic conversions.