Anthraquinones as photoredox active ligands of TiO2 for selective aerobic oxidation of organic sulfides

Abstract

Anthraquinones (AQs) are well-known for their excellent redox properties. In this contribution, AQs were designated as a photoredox active ligand of TiO2 for selective aerobic oxidation of organic sulfides. Importantly, we have found that there is an interrelation between the structural nuances of AQs and the conversions of sulfides. Particularly, with 2 mol% of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) as the redox mediator, organic sulfides can be selectively oxidized into sulfoxides with aerial O2 by 1,2-dihydroxyanthraquinone (1,2-DHA) acting a photoredox active ligand of anatase TiO2 under visible light illumination. This work highlights the potential of designing photoredox active ligand of metal oxide semiconductors to construct visible-light-induced selective aerobic oxidation reactions.