Visible-light-induced C–N bond formation by Ce(iii)-containing antimonotungstate with Ce-to-polyanion charge transfer

Abstract

The direct transformation of C–H to C–N bonds is a significant conversion for organic synthesis, pharmaceutical, and fine-chemical industries. It is imperative to explore economical and environmentally friendly catalytic systems that focus on reusable catalysts, waste reduction, and mild conditions. Herein, we present an efficient and eco-friendly method for promoting the direct conversion of C–H to C–N bonds in water under visible light irradiation using a Ce(III)-containing antimonotungstate photocatalyst, [(CH₃)₂NH₂]₄Na₂₁{[Ce₄(H₂O)₈W₆O₁₂(tar)₃(OAc)][B-α-SbW₉O₃₃]₄}·51H₂O (CeSbW, H₄tar = tartaric acid, HOAc = acetic acid). CeSbW exhibits excellent photoelectric activity with a unique intramolecular charge transfer from Ce^III to POM (W^VI) upon visible light irradiation. With CeSbW as the photocatalyst, the visible-light-induced C–N bond formation via hydroacylation of dialkyl azodicarboxylates was successfully achieved, featuring broad substrate scope, excellent reusability, and environmentally benign reaction conditions. This methodology not only enriches the synthesis strategies for visible-light-responsive POM catalysts but also provides an efficient and sustainable photocatalytic system for C–N bond construction.