Photocatalytic-Mediated C−H Activation of Toluene Using Copper(I)-Complexes with Macrocyclic Ligands

Abstract

Benzaldehyde is a key compound in the chemical industry, and significant efforts are being devoted to its sustainable production. In this study, we demonstrate that toluene can be selectively oxidized to benzaldehyde through a photocatalytic mediated reaction utilizing copper complexes with macrocyclic ligands and molecular dioxygen. The photocatalyst employed was [Ru(bipy)₃](PF₆)₂, with triethylamine serving as an electron donor. The reactive intermediate was identified as a dinuclear end-on copper peroxido complex. The reaction achieved a high turnover number for converting toluene to benzaldehyde, with no detectable side products. However, it was noted that the copper complexes underwent decomposition over time under the reaction conditions.