Photochemically Mediated Toluene Oxidation through a Copper Complex

A method is described to photochemically oxidize toluene selectively to benzaldehyde, an essential compound in the chemical industry. Copper(I) complexes with different ligands were applied in combination with [Ru(bipy)(3)](PF6)(2) and dioxygen as the oxidant. As a result, a dioxygen adduct copper complex, for example, a peroxido complex, is formed as the active species. The copper(II) complex obtained after oxidation can be photochemically reduced to the starting copper(I) species, and the process can be repeated continuously. The ligand tris(2-methylpyridyl)amine (tmpa) led to the highest conversion rates.

Automated summary

A method is introduced to selectively oxidize toluene to benzaldehyde, an important compound in the chemical industry, via photochemical process. Copper(I) complexes with different ligands, along with [Ru(bipy)(3)](PF6)(2) and dioxygen as the oxidant, are used to form a dioxygen adduct copper complex as the active species. The obtained copper(II) complex can be photochemically reduced to repeat the process continuously, with tris(2-methylpyridyl)amine (tmpa) as the most efficient ligand leading to the highest conversion rates.