Visible-Light-Induced Oxidative Coupling of Phenols and Alkenylphenols with a Recyclable, Solid Photocatalyst

A photocatalytic method for phenol and alkenylphenol oxidative coupling is reported using an inexpensive heterogeneous titanium dioxide photocatalyst with air and visible light. During the coupling process, the Ti-substrate complex is activated under visible light through a ligand to metal charge transfer effect, and the diphenol adduct is proposed to form through a radical cation. The heterogeneous TiO2 catalyst remains stable throughout the reaction and can be easily removed and reused multiple times.

Automated summary

A photocatalytic method using an inexpensive heterogeneous titanium dioxide photocatalyst with air and visible light was reported for the oxidative coupling of phenol and alkenylphenol. The Ti-substrate complex was activated under visible light through a ligand to metal charge transfer effect, leading to the formation of a diphenol adduct via a radical cation. The heterogeneous TiO2 catalyst remained stable throughout the reaction and could be easily removed and reused multiple times.