Organic/Inorganic heterogeneous silica-based photoredox catalyst for Aza-Henry Reactions

Abstract

The transformation of light into chemical energy is a leitmotiv in the development of sustainable and environmentally concerned chemical processes. Chemists invented original concepts to address this purpose, like photoredox catalysis, which became a wonderful tool to transform simple organic compounds into high-value products. Nevertheless, the most relevant transition metal based photocatalysts suffer from major disadvantages like toxicity, cost, and poor recyclability potential. To circumvent this, we propose a new generation of heterogeneous photoredox catalysts resulting from the combination of porous silica materials and Rose Bengal. They promote carbon–carbon bond formations under visible-light in environmentally benign solvent using air as the only stoichiometric redox partner. The pure covalent photocatalytic system provides a robust and recyclable system for greener catalysis. This report would be of broad significance because it addresses important sustainability issues: recycling, non-toxic metal-free photocatalysts, and less-waste-producing chemical process.