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.