Improved Effect of Metal Coordination on Molecular Oxygen Activation for Selective Aerobic Photooxidation

A pyridinium-based complex with environment-friendly and earth-abundant Zn^II ion was synthesized and explored as a green catalyst applied in activating molecular oxygen for the simple and efficient photooxidation of alcohols into aldehydes under additive-free and mild conditions. The metal coordination was conducive to promoting the electron transfer efficiency and introducing the heavy-atom effect for the increased generation of ⋅O₂⁻ and ¹O₂. Accordingly, improved photocatalytic performance of this complex compared to its precursor, no matter activity or selectivity, was obtained, facilitating the transformation of alcohols into aldehydes in a sustainable way.