Merging visible light photocatalysis of dye-sensitized TiO2 with TEMPO: the selective aerobic oxidation of alcohols

Abstract

The selective oxidation of alcohols to aldehydes or ketones is very difficult to accomplish when the oxidant is molecular oxygen (O₂) and the reaction is carried out under ambient conditions. To meet these challenges, visible light photocatalysis was exploited to enable the use of O₂ for the selective oxidation of alcohols at room temperature. In this scheme, eosin Y, an organic dye, was connected with TiO₂ to capture visible light, leading to consequential photocatalytic processes. More importantly, these photocatalytic processes can be neatly merged with the redox catalytic cycles of TEMPO, which in turn induce the oxidation of alcohols under visible light irradiation. This work suggests that the merger of visible light photocatalysis and TEMPO catalysis has great potential for execution of challenging oxidative transformations.